Oh my word! I feel for you right now. I feel like this was me in June of this year. This really brought back a lot of memories for me.
I hope for your sake that your H finds out soon enough that family is so much more important than having OW by his side. You really have done all you can do and I love that you're setting boundaries with him. He needs them! No healthy minded human being would ever want to have a R with another person on the side. He has to understand that.
I hope things go well for you in your MC meeting tomorrow. I will check back to see how things went. So keep us updated. (Btw, I'm staying cautiously optimistic for you...)
Me: 32 H: 32 M 9 yrs #1 D7 #2 S5 #3 D2 Bomb 8/12/11 H moved out 8/14/11 PA started w/H & OW in 1/12 - found out 3/24/12 Got my own place 8/25/12 H & OW move in together 9/15/12 Still married.