Yeah. It's been almost two weeks. I'm back at school, so I blame that. Apparently if I want to graduate this spring, I have to do all this work. Huh. Who would've thought…

And thanks to Kendel for her help during my brain fart.

Just fair warning – this chapter is a little more PG-13ish than the last.

Okay, read.

Chapter 10
Sexy Mistake

"Up, up, up!" a little voice called as it descended down the basement stairs.

Before Derek had time to brace himself, Jill's daughter Caitlyn had jumped on his stomach, effectively knocking the air right out of him.

"Out of bed, lazy head," she chanted, smiling innocently down at him.

"Who told you to come jump on me, sweetie? I know you didn't think of this on your own."

She answered sweetly, "Aunt Nancy."

"Well, you better go back upstairs and tell her that if she isn't nicer then Santa isn't going to bring her anything tonight."

Caitlyn gasped. "He would really do that?" she asked worriedly.

"Only to Aunt Nancy," Derek reassured her. "So, go tell her."

"Okay!" And with that, she was gone as fast as she had come.

Derek sat up on the pull-out bed, trying to stretch out his back. He hated sleeping down here. He couldn't remember the last time he had been forced to, and with the way his back was feeling, he wasn't sure how he was going to make it for two more nights.

He grabbed a change of clothes before heading upstairs to shower. His sisters and Addison were all in the kitchen as he passed through. She avoided eye contact with him as he passed.

"Whoa, nice hair, bro. Sleep well downstairs?" Amy asked, mocking Derek's hair that was sticking up in every direction. She knew how uncomfortable the pull-out was and knew he had probably spent most of the night tossing and turning.

"Yeah, usually we have to do something really bad to be banned to the basement. You'd think Mom would be happy you came home," Jill chimed in.

"Well," Nancy interjected. "He did bring Addison with him, and we all know that Mom has always loved her more than him…"

"Yes, true."

"Have I told you all yet how much I've missed you?" he asked.

"Um… no," Nancy answered.

"Good. Oh, and thanks for the wake-up call, by the way," he said, eyeing Nancy. "Don't think I won't be getting you back for that."

"I was only trying to help," she said defensively. "Nana will probably be up soon, and although she is pretty old and a little crazy, she would probably notice if you wandered through the kitchen like this when she was here."

Derek sighed and chose not to respond, instead turning to Addison.

"Hey, Addie, can I talk to you for a sec?"

She stood and followed him into the next room, out of earshot from his sisters.

"What's going on?" he asked.

"What, uh… what do you mean?"

"You. You wouldn't look or talk to me in there. I know I caught you off-guard last night, and I'm sorry if it made you uncomfortable. Okay?"

"Okay," she answered softly.

"So, do you think you can look at me and at least pretend like you like me for the next couple days? For Nana?"

She sighed. "Yes, of course."

"Thank you," he said, touching her arm.

"Go shower, stinky," she responded with a smile.

- - - - - - - - - -

Christmas Eve flew by relatively quickly. Addison volunteered to help Jane and Kathleen cook dinner, which had helped to keep her a good distance from her ex-husband for the better part of the day.

It wasn't that she didn't want to be around him. He had actually been relatively pleasant lately, and she had realized that maybe she had been missing him a little. But that kiss. It had definitely thrown her for a curve, resurfacing old feelings, both good and bad. And she was having a hard time figuring out what to do with those feelings.

Derek had watched her throughout the day interacting with his family. He loved how well she still fit in. And he knew he was lucky. Very few women would have agreed to do what she did for him. But he wanted more, and he didn't know how to convince her of that.

Eventually, his nieces and nephews had drug him outside to help them build a snowman, and he had willingly obliged. Not only did it get him away from his sisters, who unfortunately had not lost their ability to talk non-stop in the last year or so, but it distracted him from thinking about Addison. He wished his life was as simple as whether to give Frosty a top hat or a baseball cap.

Addison had been watching him through the window, though unaware of for how long. Jane had noticed the look on the face of her former daughter-in-law, and simply smiled at her when Addison realized she was watching her.

"What?" Addison asked.

"Nothing. It's just nice to have him home," Jane said casually.

"Yeah."

"Everything okay, dear?"

"What? Yeah. Of course. Why wouldn't it be?"

Jane shrugged. "I don't know. You just seem a little distracted today."

Addison forced a smile and told her, "Just tired."

The look on Jane's face made it perfectly clear that she knew or at least had a pretty good idea about what was going on, but Addison was grateful when she didn't press the issue any further.

- - - - - - - - - -

Dinner passed by in its traditional chaotic manner with the usual bickering and laughing at the "grown-up" table and the mandatory juice spilling and crying kids at the other table.

After dinner was finished and the dishes were done, everyone gathered in the living room to open their traditional Christmas Eve presents: pajamas. Patrick and Jane had started this tradition with their kids when they were little, and it had continued every year, even though there were now many more "kids" to buy for.

Soon after, everyone disappeared to get changed for the Christmas Eve service at church, and after a brief argument over who didn't want to drive and who was riding with whom, they were finally on their way. Derek had motioned to Addison while his sisters had been arguing, and they had quietly slipped away and taken off by themselves.

"Close call," Addison said soon after they had left the house.

"No kidding. There was no way we were going to ride with any of my sisters. I love them and everything, but even being in the same house with them is starting to get confining, not to mention being in the same mini-van."

Addison let out a small laugh and leaned her head back against the seat, pretending not to notice when Derek snuck a peak at her out of the corner of his eye.

"You look beautiful tonight, Addie."

She blushed a little, despite her best attempts not to be flustered by him. "Thanks. You look pretty good yourself, mister."

They made it to the church a few minutes before the rest of the clan and went inside to save a couple pews. Soon enough, the rest of the family had filed in, and the service had begun. Derek and Addison sat together in the second pew, close enough so that Nana wouldn't have any reason for suspicion, but not close enough so that his sisters would give him a hard time about it later (as Nana was prone to nodding off about halfway through the service).

After a while, though, Derek began to care less about what his sisters were thinking, and as they were all standing and singing O, Holy Night, he reached for Addison's hand and laced his fingers with hers. She looked at him, and he gave her hand a squeeze, but she didn't pull away. He let go when they sat back down to listen to the sermon, and she surprised him by reaching for his hand again.

At the end of the service, as the entire congregation held their individual candles and sang Silent Night, Derek snuck another glance at Addison, thinking about how gorgeous she looked in the candlelight and how her voice sounded beautiful as she sang along. For the first time in as long as he could remember, he sent up a prayer, asking God for just one more chance to make everything right again.

- - - - - - - - - -

Later that night after everyone else had gone to bed, Addison sat on the couch in the living room watching the snow fall outside the window. She couldn't sleep. There were too many thoughts running through her head, and she was having a hell of a time sorting them out. She was mad at Derek for kissing her and resurfacing all of these old feelings, and she was angry with herself for stupidly holding his hand all throughout the service, possibly making him believe that she was interested in something that she actually was not.

Her thoughts were interrupted when she heard footsteps behind her. Turning around, she watched as Derek entered the living room. He didn't notice her at first, as the only lights illuminating the room were coming from the tree in the corner, but he soon noticed her on the couch and stopped in his tracks.

"Hey."

"Hi," she answered.

"Nice PJs," he said, nodding at the black and white plaid pajamas she had received earlier that evening.

"You, too."

"What are you doing down here?"

She shrugged. "Can't sleep. You?"

"Same."

He sat down in the chair across from the couch, and she turned her attention back to the snow outside. Anything to keep from looking at him and saying or doing something she might regret.

"What's wrong?" he asked after a few moments of uncomfortable silence.

"Nothing."

"Bull. Something's bothering you. What is it?"

"I said it's nothing," she answered, now a little more irritated.

"And I said I don't believe you. What's wrong?"

"You!" she exclaimed.

"What did I do?"

"You kissed me! And it's messing with my mind. I moved away from you because it was too hard to be around you all the time and not be with you. Too hard to see you with someone else, who, by the way, I'm hoping you're not still with because that would make this little trip about ten times more inappropriate than it already is. And then, when I finally think I've moved on and gotten over you, you show up on my doorstep. And you convince me to come home with you. And then you kiss me. And I don't know what to think anymore."

"Then let me simplify things for you," he said firmly, standing from the chair and moving closer to her. "You left without saying goodbye. Fifteen years of history and nothing. You were just gone. I tried to move on and be with Meredith, but I couldn't stop thinking about you. So no, Addison, she and I are not together. I missed you. So I got in my car and drove down to see you. And I don't regret it. I don't regret bringing you here, and I don't regret kissing you. I want to be with you."

Addison's eyes had begun to tear up as she listened to him. But she still wasn't convinced.

"Where was this a year ago, Derek? I was right in front of your face. And you just pretended like I didn't exist. So how you expect me to believe anything you're saying now?"

"Because it's true!"

She shook her head. "I can't trust you anymore, Derek," she whispered. "I just… can't."

He took a step closer to her, and she looked the other direction.

"Addison. Look at me."

She blinked but didn't move her eyes.

"Look. At. Me."

She did.

"I'm sorry for breaking your trust. And I'm sorry for hurting you. But I'm here now. And I'm begging you to at least try."

He sat down next to her and reached for her hand, rubbing his thumb against her skin. She then noticed the ring on his finger. The same ring she had placed there so many ago. He hadn't gotten rid of it. She had thrown hers in Elliot Bay, but he still had his.

"You still have your ring."

"Yeah. I do."

"I thought for sure you'd gotten rid of it."

"I tried to," he admitted. "But I never could."

She looked down at her own left hand, examining the ring he had given her to wear the other day.

"What's this?" she asked, holding up her hand.

Derek sighed. "That is what I bought you for Christmas last year. I couldn't work up the courage to give it to you, not after what I said to you. So I was going to give it to you for your birthday instead… but by then, everything had gone to hell. So I just held onto it. Didn't really know what else to do with it."

He took her left hand and spun the ring around on her finger. "There are fifteen diamonds in it. Fourteen for all the years we'd been together, and one for all the others that were to come."

His voice sounded sad. She looked up and met his eyes, and he slowly but surely leaned toward her. When she didn't move away, he kissed her softly. She didn't kiss him back at first, but when he cupped her face with his hands, she began to respond.

She stood and he followed suit, managing not to break the kiss as they walked toward the stairs leading to the basement.

As they reached the top of the stairs, Derek pulled Addison into his arms, then reached behind, grabbing her thighs and pulling her upward. She wrapped her legs around his waist, continuing to kiss him as he carried her down the stairs.

He closed and locked the door when they reached the bottom of the stairs and then carried Addison over to the bed and gently set her down. He took her hands in his and whispered quietly, "Are you sure?"

"I'm not sure of anything anymore," she replied before pulling him toward her and kissing him deeply.

She began to undo the buttons on his pajama top. She slowly slipped the shirt off his shoulders and down his arms, letting it fall to the floor. She pulled him on top of her as she fell backward into the bed.

He met her lips with his, parting them with his tongue as he kissed her, all the while slowly undoing the buttons on her pajama top, tossing it aside after pulling it from her arms. He pulled back, admiring her in the dim light. He slipped his hands under the thin tank top she was wearing underneath and began to remove it as well. He planted a trail of kisses from her navel up to her neck as he slipped her shirt off and discarded it on the floor along with his own.

He kissed down her neck as she ran her hands through his hair, and he slowly made his way to the spot behind her ear that he knew drove her crazy. Addison let out a soft moan and arched her back slightly as Derek began removing her pajama bottoms and panties. He tossed them aside as she grabbed his face, pulling him in for a deep, sensuous kiss. She pulled back slightly, meeting his eyes as she took off his pants and boxers.

They lay together, skin on skin, briefly meeting each other's eyes before Derek attacked Addison's mouth with his own. She had one hand in his hair and the other was roaming his back. He slowly moved his hands up and down her sides and thighs before pulling her as close to him as he could and sliding inside her. She let out soft moans as he moved rhythmically with her. She wrapped her legs around his, moving her right leg up and down his left, and pressed her fingers hard into his back. Her toes began to curl as she felt wave after wave sweeping over her. She moaned into his mouth as the last one came.

Derek rolled onto his side, pulling Addison close. He pulled the thick comforter over both of them and then laced his fingers with hers and planted kisses on her forehead as she drifted off to sleep.

"I love you, Addie," he whispered.

She pretended to be asleep.

- - - - - - - - - -

"Merry Christmas, Derek. Get your ass out of bed and come help me put the rest of the presents under the tree," Nancy called out as she barged into the basement early Christmas morning and flipped on the light.

Two heads shot up from the pull-out bed at the sound of her voice, clearly confused and disoriented at the foreign voice in the basement.

"Oh, my… well, it's a Merry Christmas, indeed, eh, little bro?" Nancy said smugly as she saw Addison tangled up in the bed with him and clothes discarded beside them.

"How did you get in here?" Derek asked confused. "I made sure to lock the door."

"Please, Derek. You underestimate me. Have you forgotten that I am the master of getting into places that I'm not supposed to be? Remember your trailer? All I had to do was jimmy a paper clip in that cheap lock and—"

He cut her off. "I don't care. Get out!"

"I'll get out, but you might want to consider the fact that Mom will be up any minute now, and she may not find this situation quite as amusing as I do. Just a thought." With a smug, all-knowing look, Nancy went back upstairs.

"Ugh. She's right, as much as I hate to admit it," Derek said, flopping back down on the bed.

"Yeah… I should sneak back upstairs before your parents or your other sisters are up," Addison replied, knowing how his sisters would have a field day if they saw her leaving the basement this early in the morning.

She sat up and grabbed her clothes from where they had landed the night before, and Derek just lay on the bed, watching her dress.

"You're beautiful," he said.

"You're just saying that because you got some last night," she said, winking at him. She quickly finished dressing and began to head up the stairs.

"Wait!" Derek called out.

"What?"

He wrapped a blanket around his waist and walked over to her, pulling her in closely and kissing her intensely. After a good half-minute later, he pulled away.

"Merry Christmas," Derek whispered.

"Um… yeah… you, too. I, uh… yeah…" she stammered as she began climbing the stairs.

Derek watched her go before getting dressing himself and going upstairs. Merry Christmas, indeed, he thought.

- - - - - - - - - -

Back up in her room, Addison flopped down on the bed and stared at the ceiling. For the life of her, she couldn't figure out what had possessed her to jump in bed with her ex-husband. In his parents' house, nonetheless. And then being caught by Nancy… well, that was just the icing on the messiest, most complicated cake ever.

I can't do this, she decided. Getting involved with Derek again simply wouldn't work. She would play the part of the loving wife until they left tomorrow afternoon, and then she would tell Derek it had all been a mistake. That she got wrapped up in the moment. That holidays make people nostalgic and cause them to do things they wouldn't normally do otherwise. And a plethora of other reasons. Anything to convince him that she never meant for it to happen.

She couldn't go down that road again.

- - - - - - - - - -

Christmas morning passed by in its usual frenzy. In no time, wrapping paper was being thrown everywhere, and the kids were squealing excitedly at their presents.

Addison sat quietly in the rocking chair, holding baby Natalie, the daughter of Derek's youngest sister Amy and her husband Matt. When Derek wasn't playing Santa and handing out presents to the kids, he had been watching her as she rocked back and forth with the baby and happily watched the rest of the kids.

She'd been trying not to acknowledge the fact that she knew Derek had been watching her, even though he was making it blatantly obvious. She was hoping and praying that Nancy hadn't said anything to the others about what she had witnessed that morning, and so far it seemed as though she hadn't, but if Derek kept looking at her like that, they were going to figure it out sooner rather than later.

"This one," Derek said, reaching under the tree for the next present, "is for Addie."

Addison looked at him questioningly. "What?"

"Merry Christmas," he said, handing it over to her.

"Here," Amy walked over to her. "I'll take Nat so you can open your gift."

Addison reluctantly handed over the sleeping baby and began ripping the paper off the package. Underneath the paper was a deep red cashmere blanket. She looked at Derek.

"You like it?" he asked.

"Yeah. I do," she said, still surprised. "Thank you."

He smiled at her. "You're welcome."

Derek continued to hand out the rest of the gifts, and Addison ran her hands absently over the blanket, wondering what had prompted Derek to buy it for her. They had agreed – no presents. She had a strong suspicion that Derek had had some help with the gift, but that didn't totally stop her from feeling a little excited about it.

And for just a moment, she completely forgot about everything she had been thinking earlier.

- - - - - - - - - -

"What is this all about?" Addison confronted Derek later, holding up the blanket.

"It's Christmas. Giving gifts is kind of a tradition," he answered with a grin.

"You know what I mean. Why did you buy me a gift?"

He shrugged. "I thought you should have something to open on Christmas."

"You thought? Or someone thought for you?"

"I may have had help," he admitted. "But I picked it out all on my own. Nancy even gave her approval."

Addison didn't respond.

"Are you mad?" Derek asked tentatively.

She sighed. "I don't know what I am."

He looked disappointed.

"I really do like the blanket, Derek," she said, taking notice of how sad he looked.

"Good. I'm glad."

They sat side by side for a few minutes, neither of them speaking. He glanced at her occasionally, but Addison just stared straight ahead, seemingly lost in thought.

Finally, Derek said, "I don't regret it."

She knew he wasn't referring to the present. She didn't say anything.

- - - - - - - - - -

Addison sat alone at the kitchen table early the next morning, sipping her coffee and thinking. As much as she appreciated, and even liked, Derek's gift to her, she almost wished he hadn't gotten anything for her. He was trying to make an effort again; that much was clear. But one gift didn't make up for everything he had put her through before. She still had to tell him that it had been a mistake. But now it was going to be about ten times harder.

She was so lost in thought that she didn't notice that Nana had entered the kitchen until she sat down next to her.

"What's on your mind, dear?" she asked Addison.

Addison looked over at her and forced a smile. "Nothing. I'm fine."

"You're a terrible liar."

"I'm not lying," she protested.

"Honey, please. I may be old and a little senile, but despite what my grandchildren may believe, I'm still aware of what's going on."

Addison looked at her timidly. "You know?"

"How could I not know?"

"I don't know… it's just… everyone thinks…"

"I know what everyone thinks," Nana said. "For the past year, they've avoided talking about you two around me. They think I'm better off being kept in the dark. I've just let them believe that I am."

"So you've known this whole time?"

"Of course, dear. You two put on a good show the past few days, I have to say. It was a worthy effort."

She paused and then said, "Anyway, it's not important that I know. What's more important is what you are going to do."

"About what?"

"Your feelings for my grandson."

"There are no feelings," Addison denied. "We're divorced. We've both moved on."

Nana shook her head. "Addison. Listen to me. There is nothing worse in life than not doing something that could bring you happiness. That kind of regret… well, it'll eat you alive. Just follow your heart, honey. That's all you can really do. And the little details… they'll work themselves out."

- - - - - - - - - -

Derek and Addison sat together at the airport later that day. He looked over at her. She had her nose in a book, pretending to read, but looking at the page number, he could tell that she'd been on the same page for the past fifteen minutes. He sighed, frustrated.

Addison had barely talked to him since they left his parents' house. She had, of course, spent last night talking with his mother and sisters and had even managed to act as though everything were normal this morning at breakfast. She had hugged everyone goodbye and promised to visit again soon.

But since they had left the house… nothing.

An hour or so later, they had boarded the plane, and Derek couldn't take the silence anymore.

"Addison. Talk to me. Tell me something. Anything."

Nothing.

"Add. I meant what I said the other night. I don't want to lose you again."

She didn't move, but Derek could see a tear run down her cheek.

She finally answered, her voice barely above a whisper.

"I can't trust you anymore."

I don't know if you caught that, but they had sex. In his parents' house. And now Addison's more confused than ever.

I'm confused, too.

I'm not quite sure where I want to go with this, and since school has decided to take over my life as of next week, updates won't be as frequent. But I WILL finish this story. It just may take a while.

REVIEW, por favor.