I am SO proud of you. I am proud of you for putting a name to your fears, for plunging ahead with what is best for you and D, for not allowing H to "control" you. By control I mean letting his bad behavior, antics, and selfishness determine what you were or were not going to do. I for one was always afraid that upsetting H's applecart by somehow trying to ask him questions concerning $ or his plans for keeping the S's would somehow push us in the wrong direction, but I think now that I was just letting him take advantage of me.
I heard an excellent teaching once on the diff between being a peacemaker and a peacekeeper. I realized that I was totally guilty of being a peacekeeper, keeping the peace at all costs even when it was a false peace.
I think that your plan sounds extremely sensible. You can only change yourself as you are well aware. I know that the db protocol is to change relational dynamics by changing ourselves and the way that we relate to our significant others but I think that I was always guilty of thinking that in the overflow of doing that that there was something that I could do to change my H.
Now I am just sort of thinking that H is a hopeless case. I have not wanted to give up on him or our M, but I may have to to preserve my sanity and salvage some shred of self respect.