The legal stuff you and H have been going through has put a lot of added stress on your sitch and has probably solidified in his mind some of his reasons for wanting to leave. The WAS will look for any reason to justify their behaviour. Now that most of the legalities are behind you, H can't continue to blame you. Act as if, be pleasant when you see/talk to him, no R talk, etc. Don't give him reasons to continue to justify his actions.
The OW is an addiction. I was reading an article about infidelity and the therapist actually suggests that the unfaithful S, who will not end the A, move in with OP because this will be the beginning of the end of their R. When day to day reality sets in, the fantasy world ends. Your H will have to realize this for himself. He gave up his job and moved to another state for OW. It will only be a matter of time before he starts to resent her.
Keep rereading DR (I've read it many times); read other people's threads - this always helps me, keep posting - someone will respond. But most important, GAL - do things for yourself as you really need some pampering right now.
Me47 H46 S13 M16 Piecing since May/09
"Life is 10% what happens to us and 90% how we react to it." Lou Holtz