The DBing books are not for the spouse who wants to leave the M, they are the tools for "you". Now he has had a look at your game plan (if he read them....which he probably didn't).
My advice is to back off and stop trying to convince him he doesn't want to get a D, b/c the more you press him about it the more unattractive you are to him. He will see you as being a nag....not someone he wants to be with.
You probably won't do it, but one way for him to get a real close look at what life with the OW (as a stepmother to his boys) would be like is for you to leave the kids with him and the OW and see how well she deals with all of that. I don't mean for a weekend, but like at least a full week or more... long enough to get the full impact. It might place a big wrench in their playhouse. You know, when reality sets in...it has a way of tearing up the fantasy.
Otherwise, you need to move on aNd stop wasting time on a man who does not appreciate you. If he treated you so badly, why would you want him back?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!