Make him do teh divorce, but you LIVE as if he's not coming back and that you don't care...
You need to detach completely from him... If you show any weakness its not going to help you here...
I am really worried about this guy's maturity though... If he's willing to do THIS MUCH DAMAGE... his coming back sin't going to help you cause he's not any safer to be around than he was when he left...
My advice is to remove him from your life and life life fully, no dating. Make him file the papers and end things if its' gonna happen. Act like you don't give a damn.
When he DOES come back since YOU've been showing him indifference he's going to realize he has some work to do.. if you act like you want him back and show desperation tehn he's giong to be a lot more pompuos and full of ego when he comes back... you want the FORMER situation, not the LATTER.