If he is willing to give the relationship a chance, couple's counseling is always an option. A relationship is made up of each partner and he can not place all of the responsibility onto you. It is possible to change ones behaviors (of course as long as the person is willing to do so) Perhaps he is using that as an excuse (that you can not change) because he is not interested on working on the issues at hand. The part about his involvement w. another woman is also a red flag.
Of course, you can still work on the things you believe you would want to improve in with his or without his support.
See if he would be willing to go to couple's counseling (that will at least show you his willingness level ) at this time.