A/N: Okay, this is not how I thought it would be. I thought about Derek realizing that he is still in love with Addison and make it up to her, about they talking about their problems or something like that. So, only the first sentence is what I planned. The rest, just came to my mind and I liked it so much. I hope you do too.

Derek hadn't seen Addison since the dinner they had together, three days before. He had avoided her, trying to find a simple way to do what he thought was right. Leave her. But, God, it was becoming harder as time passed, and her words where impressed in his brain, as well as her scent and the smell of her lipstick when she kissed him.

He entered in the dark trailer, he knew she was there, probably asleep, surely with a hand on his pillow and a smile on her face.

He swallowed as he tried to look away from her, his wife, and he took his pen and the same paper she had given him. He turned it, and tried to read his own words as he wrote with no light not to wake her.

Addison, I know that I screwed up. I screwed up badly. Don't try, not even for a minute, to blame yourself for the end of our marriage. I already did this enough. And I'm sorry, because I know it was hurting you.

I guess I was just trying to make you stop loving me, but I failed. I know I failed, as well as I wasn't able to stop me from loving you.

But I had to. I still have to, and this is why I'm leaving.

You just need to know... that I want you to move on. Move on and be happy again, please find someone to love and that loves you back, and marry that person. Make a family. And, most of all, try and forget me. I'll do the same, in the short time I have to do it. I don't want you to live your life with the ghost of our marriage, the ghost of who you and me were. Move on and don't think about it that much, because I know it'll hurt.

Do this for me. That's what I wish you could have. Do this, for me, my love.

Addison. You'll always be the woman I fell in love with in med school, the most beautiful, cheerful, elegant woman in the world. The love of my life. And we will always be Addison and Derek. Together. I was wrong. I was just pretending, pushing you away from me. I was trying to protect you.

But now, I need to let you go, because even though you won't believe it, you won't understand, it is what you need.

So go, fly free, be yourself and move one. Forget me, bad times and good times, and have your happy ending.

With all my love, Derek Christopher Shepherd.

He knew he should leave now. That was the plan. Go back to the trailer while she was asleep, write the letter and go.

But he just couldn't do it. He was paralyzed, sat on the chair, and his gaze got back to the woman on the bed.

He didn't know how much time had passed. Maybe hours, or just some minutes. But at one point, she actually woke up. She woke up, sat on the bed, and looked at him with sleepy eyes.

"Derek?" she said weakly, still half-asleep.

He held a sigh and took the paper, and handed it to Addison.

She read it calmly, but anger was growing in her heart.

He was leaving her? She was supposed to forget him?

"You want to know why." he said, even though this wasn't, once again, in the plan. The purpose of all that was exactly not telling her.

Addison didn't answer, hardly containing her rage.

"I have... a brain tumor." he told her hesitantly.

"It's... not curable" he blurted, his voice lower this time. "I really want you to move on. I need it, because if not I can't leave. And that sucks because sooner or later... it'll happen."

He heard her swallow, and her breath became more heavy.

He knew it. He knew that he was asking the undoable.

xxx

It's been one year now, and she smells the white lilies as she walks in the graveyard. She's peaceful and good, and she has an enormous smile on her beautiful face.

She has a meeting with her friends at the entrance in an half an hour, but she needed to come earlier and have some time with him alone.

She sits on the grave, but doesn't say a world. All the things she wants to tell him, he already knows.

That she didn't get over him, like he asked. That she hasn't a family, but just a man to date that doesn't know yet about him. That she still imagines their kids sometimes. That she still cries in the middle of the night. That she still uses to read his letter everyday.

She just sits there, as the hot sun hits her face and warms her, making her even more serene.

And when Meredith, Richard and Mark arrive they talk about the hospital, and they make jokes and they laugh.

But she just stays quiet near him and puts an hand on her own heart, pretending to hear his beat.