A/N: This is just a little one shot that popped into my head awhile back and it wouldn't leave me alone until I put it to paper. The end result is fluffy, angsty, Maddison smut you can't go wrong with that.

Disclaimer: I don't own anything, but how I wish I did.

Tomorrow

Mark Sloan cussed himself as he raised his fist and knocked at the front door of his best friend's brownstone. He wasn't cussing himself because he was here, he was cussing himself because he was here and he knew his friend wasn't. He had purposely timed his visit that way; because he wasn't here to see his friend, he was here to see his wife. No matter how times he told himself that tonight was the last night he was going to do this, he still wound up at her door.

Tomorrow I'm gonna leave here

I'm gonna let you go and walk away like every day I said I would

Addison Montgomery Shepherd opened the door after the first knock; she knew that it was her lover on the other side, because he was the only one who knocked on the door instead of using the doorbell. "Mark, what are you doing here? We said the last time was the last time." She asked. She knew that she should turn him away, but she knew that she couldn't bring herself to do it. She would let him in and they would fall into bed just like they did every other night he showed up like this.

And tomorrow, I'm gonna listen

To that voice of reason inside my head telling me that we're no good

"Red, we both know what I'm doing here, just like we both know that you're gonna let me in, no matter how bad of an idea it is. This time is the last time." Mark replied and he walked in the door without any objection from her.

"This has to be the last time, Mark, we're gonna get caught." Addison pointed out to him. That didn't stop her from pressing her lips to his and pushing his jacket off his shoulders.

But tonight I'm gonna give in one last time

Rock you strong in these arms of mine

"Then we better make this time count." Mark pushed her up against the wall and trailed kisses down her neck while sliding his hand down the front of her yoga pants. He found her wet and ready for him. He rubbed her lightly and grinned when she let out a small moan.

"Mark, we should take this to the bedroom." Addison urged him as he kissed the hallow of her throat.

Forget all the regrets that are bound to follow

We're like fire and gasoline

"How long do we have?" Mark asked slipping a finger inside of her.

Addison gasped in pleasure before answering him. "All night, he has some big case he's obsessing over." Her hands went to his beltline. She unbuckled his belt and undid his pants before pushing them and his boxers down his hips in one go.

I'm no good for you

You're no good for me

"Good that means I can take you against this wall and then up to the bedroom." Mark replied. He hooked his fingers in the waistband of her panties and pulled them down along with her pants. He hooked her legs around his waist, put her back against the wall and thrust into her. They both let out a contented sigh as he pounded away at her.

Addison threw her arms around his neck and her mouth was open in a silent moan. "Oh God, Mark, just like that." she grabbed a fistful of his hair and pulled his mouth down to hers, so she could kiss him. It wasn't long before they both reached their peaks and he was carrying her up to the bedroom for round two.

We only bring each other tears and sorrow

But tonight, I'm gonna love you like there's no tomorrow

Mark stood looking out the window of his apartment a glass of scotch in one hand and the other clenching and unclenching into a fist. He had to give his hand something to do other than pick up the phone that was sitting on his coffee table and call her. He'd made it five days without calling her or going over that for anything that wasn't work or Derek related. He was pretty damn proud of that fact, because that redhead was hard as hell to resist.

Tomorrow I'll be stronger

I'm not gonna break down and call you up when my heart cries out for you

And tomorrow, you won't believe it,

He had even stayed strong two nights ago when he had walked past her house on the way home from the bar and not given in to his temptation to stop and check up on her. He knew that if he stopped just to talk, that would lead to something that didn't involve very much talking at all. He tried to tell himself that she was so hard to give up, because she was the best piece of ass he'd ever had, but in reality he knew that he was head over heels in love with her. If he was being brutally honest he had been in love with her since the first time he laid eyes on her in med school.

But when I pass your house,

I won't stop no matter how bad I want to

Mark shook his head to clear the cobwebs out. If he stood and let himself think about Addison for too long, he would call her. He didn't want to call her, he didn't want to want her, and he damn sure didn't want to need her, but he did. He needed her like he needed oxygen. A loud knock on his door interrupted his musings. He threw open the door without bothering to check to see who was on the other side first, deep down he knew.

"You gonna ask me in or leave me standing in the hallway, Sloan?" Addison asked him grinning seductively. She had drank half a bottle of wine in effort to get drunk enough not to call him. The only thing it had done was give her the courage to show up at his apartment unannounced.

"Come on in, Red," Mark replied with a sigh halfway between disgust and resignation. He gave her a predatory grin and licked his lips. As they had hot passionate sex well into the night, he couldn't help noticing that the protests of this is the last time faded.

But tonight I'm gonna give in one last time

Rock you strong in these arms of mine

Before long the worry of getting caught faded too. They had sex anywhere and everywhere they thought they could get away with it.

Addison looked up one day to see Mark's tall, lean frame filling the doorway of her office. "Something I can do for you Dr. Sloan?" she asked him a grin making it's way to her face.

"You can do your very best to be quiet." Mark answered shutting and locking the door behind him. He pulled his scrub shirt over his head and dropped his pants to reveal that he wasn't wearing any underwear. This was after he had made sure the blinds were closed of course.

"Mark, Derek is here." Addison cautioned him.

"He's on hour two of a six hour surgery, I don't think we have anything to worry about." Mark assured her with a wink.

"What the hell then?" Addison replied standing up. Mark immediately bent her over her desk, pulled her panties to the side, and entered her in one smooth stroke. Her walls were tight and slick around him and it was all he could do not to blow his load right then and there.

Forget all the regrets that are bound to follow

We're like fire and gasoline

Then finally one night it happened, Derek walked in and caught them in the throws of passion.

"Derek, just give me a chance to explain." Mark tried talking some sense into his friend, but Derek looked a little like a zombie at the moment, like nothing he said was registering in his brain.

"Mark, just go you've done enough." Addison told him pointing toward the door.

I'm no good for you

You're no good for me

"Blonde is really not your color, Red," Mark told Addison two days after Derek had caught them in bed together.

"Mark, now really isn't the time for your lame jokes, he left." Addison replied glaring at him.

We only bring each other tears and sorrow

But tonight, I'm gonna love you like there's no tomorrow

"I know he did," Mark informed her. "Addie, I know that you think we're a bad idea, but maybe this is the shot we've been looking for. I love you and I've made that clear to you countless times. So, it's not gonna kill us if we decide to give being a real couple an actual shot."

Addison gazed at Mark looking into his crystal blue eyes with her cyan eyes. "Ok, Mark, I've got nothing else to lose. Let's give you and me being a real couple a shot." She agreed with him.

Baby when we're good, you know we're great

Mark stood with a huge grin on his face from the news that Addison had just given him earlier. "You're positive, Red?" he asked her before he got his hopes up.

"I'm positive that I'm pregnant, Mark." Addison assured him. "Wait, you're excited?"

"Good, and yeah I'm excited." Mark answered her and he handed her a brown paper bag. "This is for the baby."

Addison smiled when she pulled a Yankee's onesie and a calendar with her due date marked on it out of the bag. "Mark, this is incredible, thank you."

"You're welcome, Addison, I didn't know if you'd let the baby wear the onesie with it being baseball related if it's a girl, but I couldn't resist." Mark stammered out nervously.

"It's perfect, Mark, you're perfect." Addison pulled him into a passionate kiss.

But there's too much bad for us to think that there's anything worth trying to save

Letting her go had been the right thing to do or at least that's what he had been trying to convince himself of for months now. He'd been the one who messed everything up and basically left her with no choice, but to abort their baby. Maybe this was for the best at least with the distance they pretty much had no choice when it came to keeping their hands off each other. That's how it should have been from the beginning anyway. She was his best friend's wife, he should have never gone there.

He should have just ignored the phone call that he got from her out of the blue one day. She had made it perfectly clear the last time he had been in Seattle that she didn't feel the same way that he did. But he did answer the phone and with just the sound of her voice all those old feelings came rushing to the surface and he was on a plane across the country before he had a chance to really think it through. This was just one last time for old time's sake.

But tonight I'm gonna give in one last time

As usual they were on each other the minute they were in her hotel room. For round one they'd barely been able to contain their lust and had ended screwing with her legs around his waist and her back against the door. The managed to get out of their clothes and into the bed for round two, quickly followed by round three in the shower.

Mark couldn't help thinking that fate was trying to tell them something when he stepped out of the shower cloaked in steam to find Derek sitting on the bed next to Addison. "Well, this is awkward." He didn't listen to fate though, and he was on her again as soon as Derek left.

Rock you strong in these arms of mine

Sixty days, all they had to do was make it sixty days without sleeping with other people and they would be home free. They would finally be able to give their relationship an actual shot without anything else standing in their way. Imagine Mark's genuine surprise when Addison was the one to break the bet and not him, but he got it she still wasn't ready for his love yet.

So, instead of calling her out for what she had done with Karev he had lied and said he was the one to break the bet. Having her think he was a whore was better than her feeling guilty. It wasn't like he wouldn't have another chance to prove to her that they could make things work, he'd just have to wait until she was ready.

Forget all the regrets that are bound to follow

When faced with the bet she had made with Mark falling apart, Addison did the only logical thing she could do, she ran and she didn't look back. She settled down in LA at a private practice and she was even somewhat happy. What she didn't count on was the pull that Mark still had on her.

All it took was one phone call from him saying that he needed her and she was on plane back to Seattle to operate on his grandchild. She never even considered not going, this was Mark he never needed anyone. So, if he said he needed her that was good enough for her.

We're like fire and gasoline

I'm no good for you

You're no good for me

One failed attempt at surgery later they were rolling around naked on her office floor together like they didn't have all that history between them. When Mark considered all the history between them that was enough for him to start making plans to uproot his life for her again and raise his grandchild with her and his daughter.

"Mark, only ask me again if you're serious and you want to actually be with me." Addison told him when they were laying in bed after another round of hot sex.

"I'm sorry, Red, I'm so sorry." Mark apologized. This time he was the one who wasn't ready for what they could have.

We only bring each other tears and sorrow

But tonight, I'm gonna love you like there's no tomorrow

Six weeks later Addison was again on a plane bound for Seattle with nothing more than a brown paper bag for her luggage.

The look on Mark's face when he opened his apartment door to his ex-lover was one of mingled shock and surprise. "What are you doing here, Addie?" he asked and then added. "After what happened in LA I would have thought you wouldn't want to talk to me for awhile."

Tomorrow, I'm gonna leave here

"This is for you, Mark." Addison handed him the brown paper bag that she had carried with her.

Mark pulled a Yankees onesie and a calendar out of the bag with a confused look on his face. "This is really nice, Addie, but Sloan took off, I don't know if she's even gonna keep the baby."

"Mark, there's one more thing in that bag." Addison told him cryptically.

Next Mark pulled a pregnancy test out of the bag and it read positive. "Addie, what is this?" he asked still clearly confused. After a second his eyes went wide with recognition. "Is this…Are you…Are we?" he questioned not making a whole lot of sense.

"Mark, I'm pregnant and you're the father." Addison answered the question he been trying to ask.

I'm gonna let you go and walk away like every day I said I would

A huge smile came to his face. "We're gonna be parents, Addie, this is great." Mark gushed.

"You say great, I say logistical nightmare. How are we gonna shuttle a kid back and forth along the west coast?" Addison asked him.

"I don't know you could move back here or I could move there." Mark suggested.

"I told you I won't be with a man who's in love with someone else I can't do that again." Addison disputed and then she saw the look on his face and she knew that he wanted this. "So, unless you're serious don't ask me again." She added.

"Addison, we're having a baby and more than anything I want us to be a family please." Mark pleaded with her.

"I'll move back here then, you uprooted for me last time it's my turn this time." Addison smiled at him.

"I love you, Red." Mark pulled her into the apartment and planted a kiss on her lips.

"I love you too, Mark." Addison replied before kissing him again.

A few weeks later Sloan showed up on their doorstep in labor.

"Addison," Mark called for his girlfriend at the top of his lungs after he had helped his daughter into the apartment.

Addison came running from their bedroom. "What is it, Mark?"

"Sloan's in labor and I obviously don't know what to do here." Mark pointed out to her.

Addison got down on the floor and started examining the young woman. "Mark, get me some towels, hot water, twine, a pair of scissors and my medical kit." She ordered her boyfriend.

"Why?" Mark asked not quite grasping what she was asking of him.

"I have to deliver the baby here, Mark, she'll never make it to the hospital." Addison explained to him quickly. "Now, go get the stuff I asked you for." She ordered him when he acted like he wasn't going to move.

Addison managed to successfully deliver the baby without any problems, but then again she was just that good. She had Sloan and the baby moved over to the hospital, so she could better attend to their needs.

"Dad, I've been like, thinking." Sloan told Mark later that day. She was laid up in the hospital bed, Mark was fussing over the baby, and Addison was checking her vitals.

"About what, sweetie?" Mark asked looking away from the baby long enough to meet the crystal blue eyes she had inherited from him.

"There's no way that I can take care of this baby. I just want my life back and I want to go home to my mommy. But you and Addison seem pretty well like you've got your stuff together and I was thinking that I really want you guys to have him." Sloan answered him.

"Sloan, I'd be honored to, but it's not just up to me." Mark told her before addressing Addison. "Look at him, Red, he's pretty great. What do you say?"

"I say we're gonna need a bigger place." Addison answered him with a smile.

"So, that's a yes right?" Sloan asked looking between the two doctors.

"That was Addison for yes," Mark chuckled. "We'll take good care of him and raise him right." He promised his daughter.

Awhile later Mark and Addison stood outside the nursery window staring at their new son. "Thank you for this, Addie." He told her gratefully.

"You don't have to thank me, Mark. He's part of you and I love you, so I can't do anything but love him? And besides this gives the one we have on the way a sibling and with my fertility issues I don't know if we'd be able to otherwise." Addison said laying her head on his shoulder.

"He needs a name." Mark smiled at her.

"I like Carson it works for a boy or a girl. And I think his middle name should be Charles after his daddy." Addison informed him.

"Carson Charles Montgomery Sloan it is then." Mark agreed kissing the top of her head.

About seven months later Carson was joined by his sister Ella Grace Montgomery Sloan followed a year later by Mark Charles Montgomery Sloan Jr. Mark Jr. was conceived on his parent's honeymoon and was an even bigger surprise than his brother and sister combined, since they didn't think Addison could have any more children.

Four Years Later

"Hey, Chief Mommy, you about ready to go for the day?" Mark asked sticking his head into Addison's office without bothering to knock. Little Mark rode on his shoulders with his little arms wrapped around his dad's neck for extra support. Carson and Ella each held tight to either of his hands.

Addison looked up from the paperwork on her desk and smiled as she took her glasses off. "You four came at the right time I just finished the last of my paperwork for the day." She answered him. When Adele's Alzheimer's started getting worse Richard stepped down as chief and had named Addison as his replacement. She had excelled at the job; under her tenure Seattle Grace Mercy West had become the number one teaching hospital in the country.

"I know that you've had a stressful day and you might kill me for this, but I told Torres and Robbins that we'd babysit tonight, so they can have date night." Mark didn't even bother easing into the subject. Right after Ella was born Callie case of baby fever had flared up again and he had agreed to father a baby for her and Arizona. The bright side of that was Addison had been totally ok with it and he still got to be daddy to Sofia.

"Believe it or not four Sloans under the age of five in the same house is a welcome stress after the day I've had today." Addison smiled at him to put him at ease. She took Little Mark off of his shoulders and scooped him into her arms. "What are doing, MJ?"

"Nothing, mommy." Little Mark grinned up at her innocently.

"Mark Charles Sloan Jr., don't give me that innocent look your father perfected that look and that's why it doesn't work on me." Addison tickled his belly just so she could hear his cute little laugh.

"Hey, don't drag daddy into this war." Mark protested playfully.

"Daddy, you're the reason this war got started all three of me get their meanness from you." Addison teased him. "Sloan called today, babe."

"What did that girl want this time?" Mark asked with sigh. His daughter had the same knack for getting into trouble that he did, but he had to admit she had settled down and she had just graduated college.

"She just wanted us to know that she got into med school" Addison answered him.

"Wow, that's great, I'll have to call her and tell her how proud I am of her." Mark beamed with pride.

"I already told her how proud we are." Addison informed him.

"You know I can't get over how great you are with her." Mark told her seriously.

"Like I've told you countless times, she's part of you and I love you so I can't do anything but love her." Addison kissed his cheek.

"Yuck, no kissing." Carson protested covering his eyes with his free hand.

"Don't be silly Carson, it's cute when mommy and daddy kiss." Ella corrected her brother.

Mark laughed at them and shook his head. "Do you ever regret any of it, Red?"

"Bringing three more Sloans into the world? Never," Addison chuckled. "Marrying you? Sometimes you give me reason to regret it, but I always get over it because I love you so much."

"Play nice, Red." Mark teased touching his forehead to hers. "I meant the other stuff before the kids."

"I used to regret it, but not anymore, because I know it got us here to this point. If I had it to do all over again the affair would still happen, that's what made us finally made us admit how we really felt about each other." Addison really didn't regret one minute of their past together.

"You know we're really no good for each other right?" Mark asked her jokingly.

"Oh, I know, but for some reason I love you like there's no tomorrow." Addison replied leaning in and kissing him on the lips. The life they had now proved that sometimes just because something might not be good for you at the moment doesn't mean it won't be good for you later on down the line.

A/N: I hope you guys liked it. Please Review.