So, you want to be married to a "better version" of him? And he knows this? And so he is "working on changing?"
Sorry to be blunt, but he really has you exactly where he wants you. He is who he is. You can either accept it, or not. But, if you wait around for him to become someone else, you will waste your life waiting for a fantasy that will never materialize. You may as well go buy some lottery tickets--the odds are better.
L