the narrator knows that he shouldn't be with this person, but there's something that keeps him around (whether the other person is stringing him along on purpose or what, who knows). he's also not quite sure what happened between them and maybe that's the reason he can't let go. he needs closure and wants answers.
here's my take on the lyrics:
the narrator knows that he shouldn't be with this person, but there's something that keeps him around (whether the other person is stringing him along on purpose or what, who knows). he's also not quite sure what happened between them and maybe that's the reason he can't let go. he needs closure and wants answers.