Unfortunately I think the only solution is to be patient, wait it out as long as you can and accept the possibility it might never happen...
As a LBS (mostly, we still live together mainly because she can't afford to leave) I can relate to your H. While I know the years of neglect my wife has dealt with were really hard on her, I think the WAS fail to understand the intense hurt caused by a spouse actually giving up and leaving. It triggers powerful feelings of abandonment and completely destroys any trust that you had in your spouse to live up to their promise ("for better or worse"). That is not an easy thing to get over.
Imagine yourself in his position. Would you be willing to commit yourself to someone who has already demonstrated that when things get tough, they're going to leave? This is what you are working against.
What can you do? Stay present, give up any expectations, be the person he would want to be with. Whatever you do, do not give up and do not give any indication you will give up. He needs to trust that you are sincere, that you are committed to sticking around and working things out. That takes time to build.
I don't know if I'll ever get to that point with my W, but I do hope someday she comes to the same realization you did. It seems unlikely right now, but at least it demonstrates there is hope. However, if we get to that point, I will then have to deal with the same issues your H is dealing with and that is not something I look forward to...
