Hey, I don't have a story of a couple who had it really rough and turned it around. I believe people can make changes and improve in time, and the fact that he goes to therapy with you may mean that he's willing to work on it. You said it's SLOW; perhaps the therapist is not that talented? I don't believe a degree can say whether someone will be a good therapist. It sounds like one who excels in conflict management and personally understands a good marriage and how to "fight" properly may be able to help ease some of the issues you are having.
There's no way from our point of view to see whether this can work between you two, but I do wish you the very best fortune.