&gt; he’s a good person otherwise

You know, murderers are not murderers, except once or twice in their lives when they kill somebody. Other times, usually fun people to hang out with!

You can't solve a personality trait. That's why therapy failed. He starts the therapy hoping there will be a solution that doesn't involve him changing himself. Once he realize the blame is being put on him, he refuses therapy, because *nothing is his fault* in life.

Couples therapy will fail. Individual therapy won't start because he doesn't think he has a problem. This is a personality trait that he needs to recognise as a problem.

Threat of divorce can actually help. But you shouldn't bluff, you either follow through with divorce or he accepts his problem.