My first reaction: you're supplicating. And that never works.
You're taking all of the responsibility for the marital failures, when SHE'S the one cheating on you?
Let me ask you: has she communicated significant marital complaints to you over the years? Or is this out of the blue?
She's obviously highly sensitive about the OM, and getting exposed. I suggest you use that to your advantage, and seriously consider exposing their affair, especially at work.
