If you believe nothing else believe that this will not be a quick fix.
You must take your focus off him and put it where it belongs, on you!
When he starts to rant and rave the best thing you can do is listen to him and validate. Do not ask any questions or defend yourself in any way. To do so will just get him riled up even more.
L, you didn't break him and you can't fix him. I know that is a hard concept to understand especially for us fixers.
Instead use that energy that would have been directed in helping your H and use it to help yourself. The only person you can control is yourself. Control your actions, and reactions. Hold your cards close to your vest and give him nothing that he can use to justify what he is doing.
Go about living your life and doing for you. Fly under the radar as far as your H is concerned.
Avoid R talks or any topic associated with it. If H brings up wanting to D, tell him that if he wants one then it be his D and that he will have to do all the work for it. Do not threaten him in any way, just try to stay calm and matter of fact. The less you say the better.
L, the one thing you have in this is time. Use it to work on yourself and fix those things that you don't like within yourself. Fix them for you, not for H.
One of our wise DBers (Cat) once told me to 'Be the change you want to see.'
Hang in there L, we're walking right beside you. You can do this!