It sounds like your wife is having an emotional affair (EA), at a minimum. If you don't have kids together, I'd suggest staying COMPLETELY dark on her, and just work on getting a life (GAL). I'm not sure how close you are with your MIL, but out of respect, I think you should send her a letter and tell her the truth about what's going on. I'm 100% sure that your wife lied to her.
I agree, the more you know about OM, the more you'll be able to know what you're dealing with. Prior to her "changes," what were her primary marital complaints, if any?
