So here is the thing. I may have done something that not all of you will like. However, it's kinda been the plan all along and there was a hint to it in chapter 2 or 3. So even if you are not expecting it, it was there all along..

That said. Read 'til the end of the chapter, 'cause there is the thing, and then some explainations and then somemore stuff, and then a moment, and more explainations and then some more stuff.

I am really really scared right now.

XXXXXXXXXX

Derek shrugged into his jacket, "I'll see you at the hospital."

"'Kay," Addison paused, kissed him quickly and returned to putting on her earrings, "Bye babe."

Derek paused at the door that led to her deck, looked back at her and grinned roguishly, "By the way, you look hot."

Addison grinned back, "Get out."

Addison left her room a few minutes later a content smile on her face.

"Morning Addison."

Addison jumped, "Izzie!" Addison tried to regain her composure, "Your up early."

"Ya," Izzie continued to look out the kitchen window.

"Listen Izzie," Addison began.

"No it's okay, it's not my business," Izzie interrupted her, and raised her eyebrow "I don't care that your ex-husband is sneaking out of your room at 5 o'clock in the morning."

"Derek was here?" Mark questioned edgily as he entered the kitchen.

"Mark, don't even start."

"Fine," Mark moved around the kitchen and kissed Izzie on the cheek, "I won't comment on how you are making the biggest mistake of your life."

"No, that was you."

"Ouch," Mark poured himself some coffee.

Addison continued to move around the kitchen making herself breakfast.

"Your going to get hurt Addison," Mark warned.

"No I'm not Mark. It's just..."

"I swear to god if you tell me that it is just sex, I am going to strangle you both."

"Mark," Addison warned.

"How can either of you possibly think that this is going to work out?"

Addison looked at him steadily, "You forget who you are talking to."

Izzie looked wide eyed between the two of them and drank her coffee.

"You think I could forget? God, you made me a part of it, remember. And I know that it worked for awhile, hell it probably kept you together longer then you would have normally lasted. But god Addison, you cannot keep doing this, especially not with him."

"It's nothing."

"Addison!" Mark resisted the urge to throw his hands up in the air, or to strangle her right there, "You and Derek are not capable of having no strings attached sex. He is not some attending that likes your hair, and your not a nurse that likes his eyes. He is the love of your life, and your..."

"I am nothing to him. He is nothing. It's nothing!"

"Did you kiss him goodbye?"

"What?" Addison slammed the lid onto her travel mug.

"This morning." Mark took a step towards her, "Before he left, let me guess. You woke up, because I am assuming that he spent the night and didn't just stop by for a quickie. So you woke up, cuddled a bit, had a little fun, maybe a shower together, to save time or water or whatever. Then you kissed him goodbye, probably threw in a pet name, and sent him back to his trailer until tonight."

Addison glared.

"Is he still seeing Meredith?"

"Among others."

Izzie raised an eyebrow, she knew that Meredith was seeing others, but she didn't know that Derek was. Other then Addison apparently.

"And are you still seeing Andrew?"

"Among others."

Mark raised an eyebrow, "But are you sleeping with any of the others?"

Addison turned away.

Mark pushed on "Have either of you slept with anyone but each other since the divorce?"

Addison turned back and glared at him as she picked up her coffee, "Don't talk to me today. And plan on spending the night at Izzie's tonight."

Mark groaned as the door slammed behind Addison.

"Wow..." Izzie murmured under her breath.

Mark walked over and wrapped his arms around Izzie, "I promise that our life together, no matter how long or short it is, will never get even a fraction as complicated as Addison and Derek make theirs."

XXXX

"We have a definite problem," Addison murmured, attempting to casually lean on the counter beside Derek.

Derek turned to her and grinned, "Do we?" he asked, reaching out to straighten the collar of her suit jacket.

Addison batted his hand away and thrust a chart at him, "Pretend to look this over," she instructed. "Mark and Izzie know."

"Know what..."

"That we..." Addison gave him a meaningful look, "She saw you leave this morning. And then she told Mark."

"I always get caught leaving," Derek muttered, shaking his head.

"Derek!" She hissed, "You have to tell Meredith."

"What? Why?"

"Because if you don't, Izzie will."

:"Izzie won't tell."

"Won't she?"

"Just tell her... tell her the truth. There is no reason to upset Meredith for nothing."

"I know it's nothing, you know it's nothing but do you really believe that Izzie is going to think that it's nothing? She doesn't know us Derek."

"So tell her."

"Tell her? Tell her?" Addison exclaimed, "Do you really want her to know? Do you really want anyone to know?"

"Addy, it's not as if..."

"As if what? Do you know how it will sound? Do you know what people will think? Everyone in New York thought that we had..."

Derek winced, he hated that term, it didn't fit them at all.

"They thought we had an open marriage. And that is what everyone here is going to assume too." She lowered her voice as a nurse neared, "No one knows here. We started over with just us. No dirty laundry, no one chasing us, or..." Addison cracked a smile, "...falling in love with us because we prioritize differently. I don't want to go back to how it was in New York. I'm to old for that brand of gossip."

Derek smirked at her sarcasm, "Are you going to tell Andrew? Or what's that other ones name... Jake?"

"Jacob. And no, I don't work with Andrew or Jacob, and they are not friends with Izzie."

"Well in any case, we have at least a day to figure this out,' Derek smiled, "Izzie won't tell her on her birthday."

Addison gaped, "It's her birthday and you spent the night with me?" she resisted the urge to hit him, "This is why we got divorced."

"First of all, it's her birthday today, not last night, and I thought we got divorced 'cause I slept with Meredith at the prom." He replied cheekily.

"No, we got divorced 'cause your an insensitive ass, which is why you to slept with Meredith at the prom."

Derek's mouth twitched, "Your somewhat irresistible when your mad," he deadpanned.

Addison glared, "Please tell me you got her something good for her birthday. You have allot of pre-grovelling to do."

"We aren't doing anything 'til the end of the week. She has plans with her friends or something."

Addison's jaw dropped, "You got her nothing for today?"

"We aren't..."

"Oh my God. Derek!"

"What?"

"It's her birthday. God. At least go get her some flowers."

"Flowers?"

"She's a girl. We like flowers. Especially on birthdays."

Derek sighed and handed back the chart he had been holding.

"Derek, either you tell her, and soon, or," she paused, "We have to end this so there is nothing to tell."

xxxx

Izzie could not stop watching Addison as the day progressed.

Addison realized this and was on edge. She was more then a little uncomfortable having her one of her staff knowing so much about the sordid details of her life. Past and present.

"Listen Izzie..."

"I just have one question," Izzie interrupted, "And you don't have to answer."

Addison closed her eyes for a moment, then sucked it up and nodded. Really, it couldn't get any worse.

"If you and Dr. Shepherd cheated on each other the entire time you were married and knew about it, how was that the reason that you split up, twice."

"We didn't cheat," Addison snapped.

Izzie was stunned, "I'm sorry," she said quietly.

Addison closed her eyes and mentally counted to 10, "I'm sorry, it wasn't cheating per say. It was..."

"Just sex?"

"Release," Addison clarified, "You've been a surgeon, you've been around the hospital for awhile. You know the things that we do everyday. The things that we see, that we have to do. Sometimes it gets to be to much. And you need to get it out. Sometimes the stress and the emotions lead you to do things you normally wouldn't," Addison looked at her pointedly, "Sometimes in linen closets."

Izzie blushed, but still looked at her uncertainly.

"Fine," Addison exclaimed, "We cheated, but to us it wasn't cheating. For us it was a way to stay sane, to not let the emotion and stress of our jobs destroy us. Compared to New York, Seattle is peaceful. We couldn't always be there when the other needed. We were the best. We were busy. So we did what we had to to survive it. But I never loved anyone but my husband, and I never turned to to anyone else when I could have been with him."

"Except Mark."

Addison flinched, "Mark and Meredith crossed a line. Mark was his best friend. I brought him to our home, to our bed. It crossed a line. And Meredith... he fell in love with her. And then it was out there, for the first time we knew for certain what the other one was doing. It wasn't something that we just did but didn't talk about. He saw me with Mark, he saw me with his best friend when I should have been with him. And he knew that it was different this time. And he told me that he was in love with Meredith. And I saw them together, and I knew she wasn't just a fling. I knew it was different."

"Is he in love with you?"

Addison smiled bitterly, "An advantage to the kind of marriage that Derek and I had, we can sleep with someone, and it can mean absolutely nothing."

"I have to tell Meredith."

Addison nodded, "Give Derek a chance to talk to her first. She deserves to hear it from him."

XXXX

Meredith squealed, "I love daisies," she exclaimed throwing her arms around Derek and hugging him tightly.

Derek shrugged humbly, "I planned something else for this weekend, but I thought I would surprise you with something for today."

Addison sauntered by, giving him and approving glance. Wearily she walked into the locker room, pausing at the mirror for a moment before making her way to her locker in the back corner. Slowly she opened it and smiled.

A red orchid.

"I heard from a somewhat reliable source that girls like to get flowers."

"We do."

Derek walked up to her and wrapped his arms around her waist, "If you want me to tell her, I'll tell her."

Addison refused to look him in the eye, "I don't know what I want anymore." she sighed, "When you tell her... if you tell her, things are going to change. It's going to be like before. Except in Seattle, so with more rain. And that's only if she doesn't murder you on the spot. She'll want you to end this, and you will, because, we shouldn't be doing this in the first place. It's complicated and just plain weird."

Derek kissed her on the forehead, "Well I will just have to make her understand."

"Oh ya? How are you going to do that?"

"I'll just explain to her that," he paused, "Your Addison. Normal rules don't apply."

Addison groaned but smiled, "It's foolproof really."

XXXX

When we live such fragile lives

It's the best way we survive

I go around a time or two

Just to waste my time with you

Tell me all that you've thrown away

Find out games you don't wanna play

You are the only one that needs to know

I'll keep you my dirty little secret

(Dirty little secret)

Don't tell anyone or you'll be just another regret

(Just another regret, hope that you can keep it)

My dirty little secret

Who has to know

The way she feels inside (inside)

Those thoughts I can't deny (deny)

These sleeping dogs won't lie (won't lie)

And all I've tried to hide

It's eating me apart

Trace this line back

XXXX

"I don't want to tell Meredith." Izzie sighed, resting her chin on Mark's chest as they lay on her bed late that night.

Mark was silent along time, "You don't have to tell her."

"You think that I should lie to her?"

"No," Mark exclaimed,"If she asks, by all means tell her but," he paused, "Derek and Addison, it's been going on for awhile. To be honest, I don't think that Meredith and Derek are any worse off for it. So if it is only going to hurt her, why tell her?"

"How long do you think..."

Mark shrugged, "Las Vegas. They were together then. She came back with her hair all braided, and I know she can't do those fancy french ones herself, but Derek has 4 sisters so he used to do her hair, which was weird and sweet all at the same time. They were together then." There was a long pause, "And the night their divorce went through, she spent the night with him, and then... I don't know, something happened between them and..."

"So what do we do?"

"Same thing I did in New York. Let it run it's course, and hope that no one gets hurt."

Izzie studied him for along time, "You love her don't you?"

"She's my best friend."

"But you love her as more then that."

"I did."

"I think," Izzie paused, reconsidering what she was about to say, "I think I want to know everything."

XXXXXXXXXX

Please don't kill me.

I don't even know where to start. I guess, send me your questions and comments and stuff and I'll either reply right to you or write a super long authors note.

And since Izzie has decided that she wants to know everything, the next three chapters are super-fun. Basically they are going to be flashbacks of New York from Marks perspective. The first one is the start of his affair with Addison, the second when Derek walks in and the next few days, and the third awhile after Derek leaves until Addison goes to Seattle.

I don't know what to say, I tried to write a paragraph here to explain it, but I can't. The closest thing I can think of would be when Izzie was sleeping with Alex but falling in love with Denny. But thats not a great comparison.

Please don't hate me.

Review.