Slowly--good point! It IS difficult to change a behavior when it's been a way of life for a long time. But this leopard has successfully changed its spots, which makes it possible for you too.
About your H and his feeling the need for closure with the OW, I can understand your disbelief but have to reiterate this strongly: let him do this. It will head off any resentment toward you if you start calling ultimatums.
I was the one in my M who had an EA and doggone close call with a PA. And I can also say with absolute certainty that if Mr. W. had told me to end my friendship with OM, I would have left and not considered his feelings. The fact is, I was getting something from OM that had been missing in my M for a really long time. I was loathe to put myself in a position of not getting what I needed.
I'm not justifying my actions, so please don't think I'm advocating this position. I just know that I needed to close that door in my own time and fashion. I finally closed that door for good a year ago (yes, several months after Mr. W. left). I lost a really good childhood friend because I allowed some boundaries to get fuzzy.
Anyway, if you give him the time and space he needs to process what she meant in the grand scheme of things, I think you can really benefit from the experience. OW is a symptom of a problem--not the cause and not the cure. Let him grieve and process... then you'll know for sure if he comes back it's because he wants to be with you--not out of obligation or guilt.
Make sense? Keep up the great work.
Betsey
"There are only 2 ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle."