She is still "stuck" not knowing what shes wants, but she knows she doesn't want to close the book on us yet. Script (am I right?). She keeps saying she wants the best for me, and she knows if we split up she will never find someone as good as me, and that I deserve better than she can give me.
"I don't know what I want" means "I really want all of these things, and I'm still trying to figure out how the get them. Please let me keep using you for the bits that OM isn't giving me, until I figure out where to get them somewhere else."
"I'll never find anyone as good as you" means "Please feel sorry for me, because of these horrible things that I have done (TO YOU!!!!) that have messed up my ability to extract what I need from you."
"You deserve better than me" is literal truth. One of the best pieces I've gotten over the last year is "When someone tells you something like this, BELIEVE THEM!"