Author's Note: Don't expect such fast updates lol. I had this written and I felt kind of bad that the prologue was pretty short so here is a longer, full-fledged chapter. Thank you for the reviews, and I hope everyone enjoys it.

Chapter One

Derek Shepherd awoke in the bedroom he once shared with Meredith, feeling the side where she should have been was cold. Derek knew he had screwed up, but he hoped that it wasn't over with Meredith. He needed to show her that Addison was a mistake, but it was hard with the constant reminder of her pregnancy. She was starting to show a little, and Derek knew it would only be a matter of time before the whole hospital knew that she was pregnant, and by him. The entire hospital knew two days after the fact that Meredith had moved out, and rumors were going around that she was sleeping with Mark. Of course, Derek blew off that notion…she hated him, but she wasn't going to hurt him that way. She knew what he thought of Mark, and he knew that no matter how much he had hurt her she would never hurt him that way.

He saw her then, at the end of the hallway chatting with her friend Izzie Stevens. The two had never been as close as Meredith and Cristina, but Derek had always liked Izzie better. Izzie had always acted kinder towards Derek, whereas Cristina acted as though Derek wasn't good enough for Meredith. And perhaps he wasn't. He didn't mean to sleep with Addison, he truly hadn't. It was just the two of them had begun to drift apart, getting busier and busier with work, and he had lost a patient that day, and getting drunk was his way to ease the pain. And then for some reason he had continued it, because he felt he needed the familiarity that was Addison, and not Meredith. He had retreated into his past, something that he would always regret.

And now here he was, wondering whether going to say hello to her would make her more upset with him. Six weeks was too long to have only passing pleasantries in the hallways, and they weren't even all that pleasant. Meredith was distant, something that was only to be expected. Before he had made up his mind his feet made the decision for him. He began walking towards the two women as Izzie's pager rang.

As she left, Meredith turned to leave and ran smack into Derek.

"Oh, I'm sor….oh it's just you" she turned away and began walking the other direction.

"Meredith, Meredith we need to talk…"

She whirled around, "talk about what? The fact you cheated or the fact that your adulterous whore is pregnant." She knew she was being hypocritical as she could very well be pregnant with Mark's baby, but it hurt knowing that he went to Addison in his time of pain rather than to her. And it hurt, knowing that they had spent eight months together.

"Meredith, please not here, come home tonight and we can talk".

Meredith pointed to an on call room. "We're talking now," and she dragged him in there.

Mark Sloan almost called into work sick that day. How he was going to face Meredith, knowing that he was nothing more than someone she was fucking to fill the void. And she quite possibly could be pregnant with his child. His child. That was something Mark had never really wanted to think about. Many a person had told him he would be a terrible father, and Addison's abortion of his baby still rankled. He hoped Meredith wouldn't abort his child, if it was his child, and go running back to Derek. He knew in his heart she would go back to Derek, because somehow he knew he would never come out on top. No woman chose him when they had Derek.

And now he had to see the two of them enter an on call room. No one went in an on call room just to talk, Mark should know. He was the participant of many an on call room "talk", and hell did he want another random woman to fuck. Sleeping with Meredith was getting too complicated with the whole "she's married to my ex-best friend" thing. And the whole pregnancy thing. And the whole "I'm still in love with Derek" thing. But Mark knew he had to continue with his life, even if it meant having his heart broken.

Meredith dragged Derek into the on call room and practically slammed the door behind her. She was angry, very angry, as she had seen Addison and Addison had been perky and cheerful. She wanted to hurt him, but she didn't know how. She knew she had to tell him she was pregnant, but she didn't know how. There were so many things she needed to say that she didn't know how to. She was an avoider, she didn't confront. And now she had gotten herself into a situation that somehow forced her to confront.

"Okay Meredith what did you want to talk about," Derek asked impatiently. He had patients to see and work to do and he had to talk to Addison about her appointment earlier this morning.

Meredith knew he was impatient. That's how he always was, trying to move on, rushing ahead. At first she hadn't noticed that he didn't seem to care, but somehow it hurt more and she wanted nothing more than to be in Mark's arms. And now she was rambling in her head about something or other, and thinking about Mark when her husband was in front of her.

"Meredith, I have patients to see and work to do and I have to talk to Addison about her appoint-" As soon as the word Addison left his mouth he saw Meredith's eyes narrow and realized that he had made a big mistake.

"Addison. ADDISON? Derek, that's all you ever talk about. Your precious Addison. What if all I ever talked about was Mark?" The moment the words had left her mouth she regretted them as it was Derek's turn to have his eyes narrowed.

"You're sleeping with Mark?" He asked in a dangerous whisper.

"You're still sleeping with Addison" she accused.

"This is not about me Meredith. It's about you sleeping with my worst enemy!"

"Derek, you are now being hypocritical. Your wife cheated on you and you turn around and cheat on me with the same wife five years later? Derek, be reasonable."

His hand came up and made contact with her face. The smacking sound reverberated through the tiny room and Meredith's hand flew to her reddened cheek. Tears welled in her eyes, not from the physical pain but from the emotional pain.

"Meredith, I'm sorry, I overreacted."

"Now you realize. I never want to speak to you again"

Meredith left the on call room, leaving Derek standing there, with tears streaming down her face. She ran into Mark, but without even an apology ran into the nearest supply closet. Mark glared towards the on call room, wondering if he should hurt Derek for hurting Meredith so obviously or to comfort Meredith. Then he wondered why he cared. She had made it quite clear they were only fuck buddies, but for some reason he thought he might love Meredith Shepherd. So he followed her into the supply closet and found her there, curled up with her knees up, putting her face in her knees.

"Meredith…" he said gently, hoping his gruff voice came off kindly and gently.

She raised her head and it was all he could do to suppress a gasp when he saw the red handprint on her face.

"Mer, did Derek hit you?" His words evoked a new wave of tears, but Meredith managed a nod.

"Why Mer?"

"I told him I was sleeping with you," she said with a watery smile.

Mark was shocked. He never really expected Meredith to tell her husband that they had been sleeping together, even though Addison had told him that she was continuing to sleep with Derek even after their drunken encounter. For eight months to be exact. Mark didn't know exactly how much Meredith knew, but he never expected Meredith to tell Derek. He expected her to go running back to Derek, leaving Mark to watch the two make a happy family with what was quite possibly his child. And now, he had a chance. He truly had a fighting chance.

"Did you tell him you were pregnant?" The moment the words left his mouth he regretted them. He saw how her eyes dimmed and he should have known not to bring it up. He wasn't used to the emotions that went along with sleeping with your ex-best friend's wife, and the emotions that went along with falling for her.

"I don't even know whose baby it is" she said, crying harder.

He sat down next to her and pulled her into his arms. "It's okay, it's going to be okay Mer." He stroked her hair, holding her until she fell asleep. He had never been this comfortable with another woman, not even Addison.

She woke up about an hour later and softly kissed him on the lips. "Thank you Mark."

"Anytime babe," he replied, and he truly meant it. Mark Sloan was not often comfortable holding a woman, just holding her and comforting her but for some reason he was with Meredith. He might not want to admit it to himself, but he thought he might be falling in love with his ex-best friend's wife.