could be that he wants to be with someone else now. In all reality, it is the most healthy thing to do when a partner cheats on you... staying isn't really great for most(even those that have made the decision to saty married are frequently unhappy with that choice)...but he DOES have the incentive to also work things out for your daughters sake. For that reason, I really think he should try and forgive you.
I think exposure will backfire because now that he is living on his own and you cheated... most people will not agree that what he is doing is wrong. Heck, I have been cheated on and hate WS... but I can tell you that if I were married and made the decision to leave my wife after she cheated that I would not consider myself married and cheating if I chose to start dating again. I would just be waiting for divorce papers. Doesn't sound like that is where your H is at... so this is really a gray area. But I do believe that exposure will create an environment that gives him MORE support for what he is doing instead of less. I would be careful with this.