I'm trying to put myself in your H's shoes as best I can to understand where he's coming from. I agree with Atlas and Himey that your H really seems to be dictating as much of the sitch as he can, and my opinion as to why is simply because he's losing control in general. This was my problem when my W left. Yes, once she actually chose to leave, get her own place, etc, I did a lot of good and noble things for her, but I still tried control her by giving her a time limit on the "time" she needed away from me (I didn't find out about DBing until several months later). I forced her to make a decision about us a mere six or seven weeks into the separation (which seemed like an eternity then, but more like a pimple on the #ss of time now), just so I could have some control over something. Of course that move backfired, and then I filed for D 3 weeks later in another attempt to regain some control. Again, "boom!" right in my face.
I'm going to create an analogy for what your H is likely going through in my mind. I see your H climbing a steep hill (your failing M) where the ground suddenly begins sliding away from underneath him (you walking away). As he is sliding away with it, he's panicking and desperately trying to grasp onto what he can in order to not lose his position on the hill -- any root, rock, bush, tree branch, etc, will do (which translates into things like your house, daughter, etc). What he doesn't realize is that he's this side of the hill can't be climbed (this form of your M is not doable/livable), and he is wasting his time and energy trying to regain his footing and continue on. He needs to exercise patience and sound judgement, and realize that he needs to go back to the bottom, reassess where on the hill to resume the climb, and start over with new perspective (work on a new R with you with a new understanding on how to have a better M with you). Problem is, H is hardheaded, and refuses to admit that he can't climb that side of the hill. It is a blow to his pride, self-esteem, etc, and he just doesn't want to admit that he can't do it (that he has no control over this failing M continuing the way it is). Don't know if that helped at all, but that is more or less how I see it.
I think I've said this to you before -- actually moving into your own place might just be what H needs in terms of the 2x4 upside the head to get him thinking about what he needs to do to save his M. Heck, you may even have to file for a Legal Separation for him to "get it," and even then I think it will take some time for things to sink in before he has his "Ah ha!" moment. I don't think that this is a DR recommendation by any means. It is a risky move because, like my filing for D, it can blow up in your face and simply move the Divorce process a long quicker. However, I don't know what Michelle's advice would be to you as the WAS. It would be awesome if she could write a book on what WASs who want to save their marriages can do (or at least include a section on that in DR).
As far as visitation/custody with D4, I'm not sure what you will have to do to get H to be agreeable and fair with you. Maybe (and I know you don't want to do this) talk to his parents and bring this issue up. I'm sure they wouldn't approve of H using their granddaughter as a pawn in this chess match. I would also consult an attorney to see what your rights are on this matter.
It is simply amazing that H doesn't realize how helpful you are still being despite his poor efforts. Maybe it is time to become more assertive -- you really do hold most of the cards, waw. Maybe it's time to start playing some of them...
