Ohhh Kim!!!!!

You are entering into what I consider to possibly be the hardest part of DBing. Possible reconcilition.
Brace yourself for some roller coaster rides here.
Kim, I cannot help you with taking this into the right direction, but I can tell you that I know this is an important time in your sitch. to handle things very carefully and to also really take care of you.
Your H's words are what all DBer's want to hear, but you are so right and your head is on right to wait and see if he can walk the talk.
You know, I've read that A's are very very difficult to break off and so I think you are aware of the threat of him doing this and then going back or of him not getting the strength to do this. I think HE is going to need a lot of support to do what it is he wants to do. I don't know that YOU can provide this support yourself. When people do break off A's they tend to mourn a loss themselves, and this makes them think they should go back into the A.
If he can really do this Kim, I think you ought to get him some books..after the affair, etc.
I also think that with all the incredible effort and strength you have inputed into this DBing effort, you must be very cautious to not throw it to the wind. You are going to start wanting to have your needs met, as he seems to be wanting to improve things, that is going to tempt you to start asking for a lot. Be careful to not get demanding or place too much pressure. You have def. said your piece and you have set your boundaries and you have basically given him an ultimatum of sorts. So what I suggest now, is that you do not repeat what you expect. He knows it, he is feeling pressureed and stressed about ending it. So I think you best ought to at this time NOT mention OW or if he broke it off yet...he knows it is on your mind...let him bring it up and share with you. And meanwhile you keep strong and don't deliver any demands or ultimatums. You are getting close possibly if he can be strong. It may be harder for him than we know, so I suggest if he doesn't do it NOW, that you think very carefully before saying anything.
Perhaps now would be a really good time for you to schedule a session with a DB coach to help guide your actions. The LRT does not give insight into what to do when things progress...and this is where guidance could be really useful. What your doing has been working, but now you are changing the game plan, but you need to keep doing what is working. I want to see this work out for you, and I think H is turning a corner, but we all know it simply isn't so easy as "the fog" lifting and things getting back on track.
Kim, maybe you ought to seek out some other DBer's who have been here and guided the course of the M back on track.
I wish you lots of luck. Keep optimistic, but stay detached and healthy too.
You are doing fabulous Kim. Keep up the good work.