I know you got plenty of great advice here but I just want to tell you good luck and that I hope you can find the strength to let him work on his issues on his own, nobody deserves feeling like **** and unwanted from their SO.
If he is open and willing to take the steps to improve the relationship, then great. It may be slow but he needs to be actively TRYING.
If he does not want to fix things with himself -- and his relationship with you -- then you have your answer.