A/N: OK so I know that this story has been done before BUT I have always loved the Mark and Addison story and just wish we could have had some real background on the couple. So anyway this is just my take. It will just be snapshots of their lives through the years.

I hope you like it please review and let me know!!!

THE ENGAGEMENT

Addison stood at the bottom of the stairs that led to Marks apartment. She had been dreading seeing him all day. She knew he knew that she was now engaged to be married to Derek. Mark was the first person he called after she said yes.

She took a deep breath and began her ascent up the stairs. Now she was standing in front of the door, she knocked softly, when she had no response she knocked a little louder.

Mark knew exactly who it was he had been expecting to see her this evening. He had contemplated going out, getting drunk and getting laid by some random woman. However he knew that he had to have this conversation, so he rationalised that it would be best to get it over with. Just wait for her to turn up.

He opened the door, just looked at her and motioned for her to come inside. They were not having this conversation in the hallway for his neighbours to witness.

Addison moved through the space he had made and turned to look at him. They stood there like that for what seemed like an eternity before she spoke.

"Aren't you going to say anything" She said quietly.

"What exactly do you want me to say Addison? Congratulations?" He said with a cool calm that was almost icy.

"I don't know what to say Mark. I'm sorry I never wanted to hurt you"

"Then go back and tell him you changed your mind, tell him you don't love him, tell him you don't want to marry him" He said angrily

"I can't do that, Derek loves me, he wants me to be part of his family"

"I can be your family"

"What about Derek? Mark he would be devastated if he knew about us. I can't do that to him."

"Don't think for 1 second that I don't know how much this would hurt Derek. He is the only family I have too. But Addison god I love you I'm prepared to take that risk. In time he would get over it"

"Mark stop we can't do this anymore"

"What about me Addison? What do I mean to you? I have known you for 7 years, I know what we have isn't just a fling."

"It's not Mark, a part of me will always love you but we both know that we couldn't work together, not really"

"That bullshit and you know it" He yelled

"I know that Derek would never hurt me"

"And you think I would? That's it isn't Addison? Derek's the safe option isn't he?" Mark was still yelling

"Yes Damnit is that what you want to hear? Derek is the safe option. I love him in a comfortable, safe, secure way. He loves me in a way that I have never experienced before"

"That's because it's love of friendship and family Addison. It's the love of his whole family that you don't want to lose because you never had it growing up just like I never. The love that you two share is of two people who care about each other. It isn't the passionate, can't be without each other love is it?

"No" Addison mumbled

"God what the fuck are you doing then? The whole situation is ridiculous. All 3 of us suffer. Derek deserves better than being someone's safe option. I don't deserve to have to spend the rest of my life pining after my best friend's wife, and you deserve to be with a man who you desire, who isn't just safe and secure"

"Mark please don't make this any harder that it already is" Addison said tears fighting their way down her face. The reality of what Mark was saying was true, but it was too late, she wasn't going to change her mind.

"I guess if that is your decision than we are done. But you can't expect me to be at your beck and call, just waiting for you to come back to me"

"Mark I can't lose you, please don't shut me out of your life. We have been friends for years, I don't want to ever lose that." Addison was nearly begging him now as she threw herself into his arms.

Mark had next to little will power when it came to Addison she was his weakness, his Achilles Heel. He wrapped his arms around her and held her close to him.

"Baby please don't cry. I hate it when you cry."

"I'm sorry Mark, so sorry. I know I'm being selfish and completely unfair, I 'm just so confused"

"I know you are which is why you have to tell Derek, that your answer is no. Addie you can't marry him if you feel like this. "

"I am getting married Mark, it's what I want. We can't be together anymore, once I'm married we can't do this anymore" She looked up at him and gently brushed her lips over his.

Mark pulled her closer and deepened the kiss; he ran his fingers through her hair, held her face, as his tongue entered her mouth.

This was the kind of love Mark was talking about earlier. He only had to touch the side of her face, run his fingers through her hair, kiss her softly and she was complete putty in his hands. Derek never had that effect on her which was what led her to Marks arms all those months ago.

They had been having an emotional affair for years, it was only the last 6 months that they finally acted on their feelings. They started off rationalising that it was a one off, a mistake that would never happen again, but a week later Addison was in Marks bed again.

"Just this last time Mark" she breathed into his ear after breaking the kiss.

Mark just stood up and held his hand out to her, she put her hand in his and he led her to his bedroom.

They took each other's clothes off slowly and fell on the bed as they began to make love. He kissed her neck and moved his hand down to caress her breasts. She reached down to feel his erection she needed to have him inside of her. This would be the last time they both thought to themselves.

Mark entered her slowly, letting her adjust before he began trusting inside of her, slow at first, he wanted this to last for as long possible. As their desire for each other increased his trusting became harder and faster. They both screamed out as their orgasms took over their bodies.

"I love you" Addison whispered as she lay her head on his chest.

"I love you too, regardless of what I said earlier I will always be here for you. Maybe not like this but..." He trailed off

"Thank you"

Addison left half hour later. They both wanted to believe that that was the last time they would be together. Derek meant too much to both of them.