Grey's Anatomy, Season 2

Derek:
So I go upstairs, as I'm walking down the hall I'm trying to prepare myself for what I'm going to see when I go into my bedroom. I step on a man's jacket that doesn't belong to me. And everything I think I know just shifts. Because the jacket that doesn't belong to me is a jacket that I recognize, what I know now is that when I go into my bedroom, I'm not just going to see that my wife is cheating on me. I'm going to see that my wife is cheating on me with Mark, who happened to be my best friend. It's just so pedestrian, common and dirty, and cruel. Mostly just cruel. I left, came out here.

Meredith:
Then you met me.

Derek:
And I met you.

Meredith:
What was I to you? The girl you screwed to get over being screwed?

Derek:
You were like coming up for fresh air. It's like I was drowning and you saved me. That's all I know.

Meredith:
It's not enough.