Jake I think you need to stop stressing about whether it happened or not. If you can't let it go just assume she did.
I mean will it change your response whether she did or not? Will you walk out on the M?
Seriously based on all your evidence I think you should just assume she did. See if you can handle the thought.
The way your W sounds she will never come clean about what really happened. When she talked about her sister's affair and how her husband would react she was gauging your reaction. She was waiting for you to say something ridiculous so she could further justify lying to your face.
Look the truth is simple she has lied to you in the past, so you don't trust her. No surprise. Why are you trying so hard. No matter what she says it'll probably never quell your suspicions or fears. So accept it, she most likely had sex with him. How does reading that make you feel?
What will you do now? Dwell on something you have no control over, because it is in the past?
