If CP is part of H's problem, then I can only assume that if he and I were to file and D., he might then view his R. with o.w. as more trapping than he sees it right now.

Yes, that's a possibility. It's also a possibility that the OW may be uncomfortable having him freed up and dumped in her lap. It's also possible that H may escape any suffocation with OW by having another OW. Or by calling you back up (but that would suck!) And so it goes.

I actually wish he would spend some time alone (no o.w., and also not officially back with me) because I think this is what he really needs.

Forget about what he needs, dearie. What do you need that has nothing to do with him?