Smallville, Season 6

Oliver:
Ever since my parents died, I've jumped around from city to city, from continent to continent and in all those years, not once have I regretted leaving anyone. But then I met you.

Lois:
Then stay.

Oliver:
I can't. Because there are more important things in this world than what I want.... and what I love. Someday I can explain why.

Lois:
Don't expect me to be waiting around for that when you get back.

Oliver:
I'm not coming back, Lois. At least not any time soon. I'm sorry. I never wanted to hurt you.

Lois:
Well, you finally got around to it anyway, didn't you?

Oliver:
This is it, the moment, right? The moment that I'm gonna regret for the rest of my life, isn't it?

Lois:
Yes.