My wife consistently lied to me and to our family (our adult daughters and my MIL and FIL) about her affair. "He's just a friend" was her stance throughout, until I finally confronted her on that "deceit" part of it, as the lies were just insulting my intelligence.
Yes, you should act "as if" -- AS IF THIS MAY NOT BE WHAT YOU WANTED, BUT YOU REALIZE YOU WILL BE PERFECTLY FINE ON YOUR OWN IF THAT'S THE WAY IT GOES DOWN. BIG difference than acting as if you're okay with his cheating.
"Hey, I think what you're doing is disgusting, cowardly and -- frankly -- unattractive. But you're a grown man, and I don't wish to control you. You do what you want, but I'm not willing to live in an open marriage, and I realize now that while this isn't what I wanted, and it will be difficult, that I'm going to be just fine."
That should be the attitude that oozes from your every pore.
