Well, if you are waffling, you can be sure he's going to do his best to convince you that he has changed. A few months of therapy and putting his best foot forward is a small price to pay to get you back. The thing is, you have spent several years with him already. He has lied, cheated on you and treated you horribly. Until you actually live with him again, you can't possibly know that he won't return to the same person he was in the past.