Erin, would you still want him back? That's the key question.
If you do still want him back, then you are not at the end of your rope by any means.
Quote: The thing is, he still says he is only 95% sure. I asked him why he would go forward, with such serious consequences, when he is only 95% sure. He doesn't know.
An affair is a kind of addiction, Erin. He is addicted to the OW the same way a druggie is addicted. He feels that he can't help himself. Trust me when I tell you that he's very unsure and will become more so in the near future.
From what I can tell of your emotional state, I would advise you to "go dark" at this point. That's what Michele calls the "after the last resort" technique. You absolutely, completely stop seeing him and talking to him. If he wants to visit with S2, then you drop him off at your MIL's or somewhere else and then pick him up. If you have to communicate about something like taxes, do it in writing.
I did this for three weeks and it was amazing how much hurt and anger I was able to get over during that time. I could relax, because I never had to worry about what I was going to say to my W or what she was going to say to me.
You can either do this for yourself for a while (like I did) to get your emotions together, or you can decide to do it permanently and let him know that you won't speak to him until the A is completely over.
This also has the added benefit of forcing your H to come out of his fantasy world and face reality.
Good luck!
The LORD is near to all who call on him, to all who call on him in truth." (Psalm 145:18)