Hi Kim- Have you ever heard of the 3 R's? Remorse, Repent and Repair...that is what your H needs to be trying to do. I may be totally wrong, but if my H had an A, I would be hesitant to reconcile if my H wasn't willing to do whatever it takes for me to feel comfortable in the R. Though, if your H is having a MLC, maybe all bets are off and you just have to try to survive the rollercoaster until he comes out of it.
I just got the Divorce Remedy by Michelle Wiener-Davis. I am just getting to the 3rd step, but I think she has a lot of great advise. Maybe you should check it out. There is a chapter on infidelity where she states about S that had the A "you owe it to your partner and yourself to bend over backward to prove your trustworthiness".
My H left 3 months ago (claims their is no OW), he said he just wasn't happy, wasn't sure he wanted to be married and pointed out everything I had done wrong since we have been married. Things are getting a little better now. We have had several sessions with a MC and we are both getting IC. My H says he want to take baby steps, but I am struggling with what those steps are. On top of that, even though he claims there is no OW, I have difficulty trusting him. He isn't ready to come home yet, but when or if he does, I know I am going to need a lot of reassurrance from him...but on the flip-side of that, it might be best for our M if I just try to let go and have faith...what do you do????
I wish you lots of strength to get you through this.