"Umm…" I stare at her. Is she serious?

She's looking at me expectantly from where she's sitting against the wall, tucking her knees up to her chin like a kid. I feel strange standing above her, so I sit down on the floor across from her. This is definitely one conversation I never thought I'd be having.

"How did it even begin? You can tell me. I can take it. Seriously." She looks genuinely intrigued and almost eager.

Then it hits me – has Derek ever told her? About how it started and what it became? It's never occurred to me before… but everyone in this hospital can tell that the two of them don't have the world's best communication. I wonder if he's never even bothered to tell her the story, and I can't help feeling a little sorry for her that he shuts her out so much.

"Okay." I tug on my long ponytail, an old anxious habit. "It started out as a one-night stand. I didn't even know he worked here."

"You're kidding."

I shake my head. "Then I came in for my first day of work and there he was."

"You must have died," she said with a smile.

I can't help returning it as the memory flashes through my mind. "I did. I ran away, actually. I couldn't believe that a drunken hook up turned up as my boss' boss."

She waits for me to go on. I find it hard to believe that the woman actually wants to hear this. It must be killing her… and does it make me a horrible person if I take a small satisfaction in telling all this?

"I wanted to end it right there," I go on. "But he kept chasing after me, begging him to go out with him. Finally I caved."

"He's very persistent," she says softly.

"Yeah. So then he was practically living at my house… and we just got along so well. It was good. Too good to be true, I guess." I shake my head slightly, coming back to reality. "It was all a lie. All of it. The entire time we were together… he had you. He had a wife. And I had no idea."

"He should never have done that to you." She looks pained, but thoughtful. "I didn't… I mean, neither of us knew where we were going in those three months. I was in New York, he was here. We didn't call or talk or send divorce papers or anything. We were in complete limbo. I guess we just didn't know how to deal with it. And he dealt with it by pretending I didn't exist," she said with a slight tone of bitterness.

"But now you're… you know."

She looks away. "Barely. He just acts like…" She stops and looks at me again. "I'm sorry. You don't want to hear this."

"No, it's okay," I say, and wonder if it's true.

She sighs. "He's still not all there. He's not in this. He's still in love with you, and he's just waiting for it to pass over or for me to leave him or something, anything, to happen. He looks right through me when he sees me. I'm just – " I realize in amazement that her – Addison Shepherd's – voice is cracking. "I'm just so scared of being invisible. I was invisible before and look what happened because I couldn't take it. I'm just so scared." She leans her head down on her knees.

I feel my mouth drop open slightly. Oh, this is just fabulous. I'm with Mrs. McDreamy stuck in a freaking elevator and she's about to have a mental breakdown.

"Dr… I mean, Addison…" I look around as if for someone to help. Oh, that's clever, Meredith. Look around the ten by twelve foot elevator and maybe someone will pop out of thin air and tell you what to do.

She lifts her head and I can tell she's holding back tears. "I'm sorry. I don't do this. I don't cry."

"I know."

"We were… we used to be perfect, once upon a time. We were so in love and so obsessed with each other and we never stopped laughing. We spent every second together, you know? We worked the same hours, we were never apart if we could help it. We fought, of course, but it's just because we're both so goddamn stubborn." She smiles slightly and is looking straight ahead, at a memory I can't see. "And then it just all changed. I wish I knew when, or how. I wish I could go back and pinpoint the moment when we stopped talking and decided that becoming world-class surgeons was more important than each other."

Well now really. What am I supposed to say to that?