Why isn’t love enough?

Alice: Will you hold me? I amuse you, but I bore you.

Dan: No, no.

Alice: You did love me?

Dan: I’ll always love you. I hate hurting you.

Alice: Why are you...?

Dan: Because I’m selfish. And I think I’ll be happier with her.

Alice: You won’t. You’ll miss me. No one will ever love you as much as I do. Why isn’t love enough?