I wouldn't expose anything about your H's A until you know for certain - and I mean can prove- that it exists. My H had admitted it to me. The kids found out at the same time because they heard me screaming about it and going mental. I had on occasions wondered about this particular woman as H had kept going on about how nice she was and how if I knew her she was the type of person I would be friends with - hmmmm - yep - I really go fo husband stealing cheating b!tches - riiiiighttt!
I think I had a few distinct advantages that worked in my favour.
Before knowing about the A my H had seen that I was trying via the C to make changes in our M; so he knew the changes were for real - there was never any question that I was doing it just to save the M because I had found out he was having an A. (You seem to have this in your favour too from what you say).
The A had been going on for 18 months so I wasn't dealing with that overpowering hormonal love rush that a lot of people on here are dealing with in their S when they arrive. My H had gotten to the point when a lot of A's break down because the highs have dissapated and the practicalities of following through on the pipe dreams are beginning to look not very realistic. I dothink men often give up at this point because they no longer have that intial high that gives them the energy to deal with the agro of a split.
I knew for certain about the A as the info came from my H and he gave me access to OW and all her correspondence etc.
Also my H had much to lose too. He would have lost his position as the CEO - he knew I would have seen to that as he would have been seen to be abusing his position.
I am an advocate of 'busting' an A. It worked for me. I know though that it doesn't work for all and I can't see how it can be done without proof. I don't understand how a M can be worked on when there are three people in it....but that is just my opinion. It's hard enough with just two of you and your own children.
Good luck - I think you have reasons for much hope. Stick with it.
Saffie me 46 H 46 M in 1986 D20,D18,S16,D13 H's A 01/05 to 07/06 H recommitted to M 07/06 renewed vows 09/06 Going from strength to strength