Amy, I'll try to be a voice of reason here. I still don't see where forcing him to get his own L, file, and go through this confrontational process serves you in a good way; other than to exact revenge for the exposure of the kids to the OW. I understand your rage and anger because he broke a verbal committment. Well, that's not the first time he's broken a committment, now is it? Yet, after that broken vow you were able to maintain a friendly tone with him.
Maybe this is just me; but if you have what you want from the settlement and he's still willing to oblige; I submit that you avoid the extra costs and heartache of a protacted divorce.
I know that "Hell hath no fury like a woman scorned." But take a look at the real reason you want to go this route. Is it REALLY the best way for yourself and the kids? Or is it just revenge?
Just my $.02; ultimately you will decide what's best for you.