Her peer groups are never going to help him out. I believe in the 180 and the steps on DB wholeheartedly.
I believe however that there are elements you can introduce to your situation to help it be more in your favour.
As long as his wife is running to these divorced friends, he really has literally zero hope except taking care of himself. The purpose of the DB site was to provide hope and solution for those who may be headed directly for a divorce.
We all agree on DB, that yes you have to take care of yourself - but there are some other things that you can do, which help your esteem and let you feel less "powerless". One of them was an effective "affair bursting".
He has to take care of himself whether he waits on a reconciliation, or if he leaves. However, moving to a "Christian" oriented frame, where you may make new friends who are a friend of marriage, can only help you. Or to simply expose that the W hates the institution of marriage.
What better closure than that? What more could you have done?