Bones, Season 4

Sweets:
Does it seem that your partnership provides a surrogate relationship, making it more difficult to form other bonds?

Brennan:
A surrogate relationship wouldn't necessarily be such a bad thing because then I could avoid the sting of rejection, which, however fleeting, is still uncomfortable.

Booth:
Right. Okay, look, I'm sorry. You know what? If Mark and Jason don't know how lucky they are, they don't deserve you in the first place.

Brennan:
No, relationships are temporary.

Booth:
No, that's not true, Bones, you're wrong, okay? There is someone for everyone, someone you're meant to spend the rest of your life with, all right? You just have to be open enough to see it, that's all.