Plagued by the “what if’s”? How do you know for sure that he hasn’t had a miraculous “healing” that his fairy God Mother didn’t twang him in the middle of the night and give him a heart and soul?
There is one simple way to know if he has truly changed. If he had changed he would not be lying about you now. If he had changed he would own his own shit. He would not be slandering you, lying about you, trying to destroy your life; he would simply go on with his life, happy to be free of you, if you were such a bitch.
Do you know any healthy person who is that vindictive? Ask yourself what would you must have done to drive a perfectly sane and reasonable man to the point where he wants to destroy you now?
Healthy people do not go on a vendetta to destroy their ex lovers, they just don’t. Healthy lovers don’t blame everyone else for their shit and they really don’t enjoy inflicting pain on anyone, even their exs. If he had really changed he would have to have come to some realization that he was at fault at some point, if he is still insisting it was all your fault, he has not changed.