One more question -piece of advice. I've been practicing the speech. Think I have it down. Last time, she got very defensive, accused me of spying, etc... Probably going to happen again. My initial thought is that I need to just walk away after I say my peace and not stay around looking for a response. Should I engage her if she wants to have a R talk? I know it probably will depend, but I'd like to have my whole strategy worked out. Last time she turned it all back on me and she ended up leaving the house mad at me and we didn't talk for weeks.
Generally when you confront you have to be prepared for the fact that your M can end due to the confrontation.
I'd be firm and take all the deflecting, etc. and just focus her on the fact that she is having an A and you cannot discuss any other issues until she ends the A.
If she walks out? You are better off if she's going to continue cuckolding you.
"You can't reason someone out of a position they didn't reason themselves into."