I hope you'll forgive me for saying this, but your H sounds like a creep. I know that's not productive or helpful at all, but I think he deserves a little name calling. Even in some of the worst cases here, I don't get the vibe that I do from your sitch. If you're mentally and emotionally prepared for the potential outcome, do it. Go dark. Be sure before you do. But I'm just not sure he can be reached with standard DB techniques. It seems to me that most people here have what they believe to be a solid foundation. It looks like your foundation is broken.
Tell me, Casey...What makes you want to save your M at all? I don't mean that sarcastically; it's a real question. I know you want what's best for your d, but what else is there? If you didn't have a d, would there be anything there for you?
What do you love? Do you love the person, or do you love the comfort of your life and the idea of your H? Is there anything there for YOU?
Please think about those things. Make a list of all the reasons you want to fix your M. Then wait a day and re-read it. See how many of those things involve the love between you and you H. You may find lots of things and lots of reasons. Or you may find hardly any at all. But if there's nothing between you and H and you feel like you don't have much to lose, then I say go dark. Ideally, it would wake him up to reality and he would become willing to make some changes, but you must be prepared for the worst.