The more she's talked about it the more I'm being swaying by fact my W's father died in her mid teens which totally rocked her world as he was her world, and she viewed OM as a sympathetic father figure (he is 12-15 years older) who listened intently and told her the nice things she wanted to hear, things a Dad might say. Please comment on this as my bull**** filter is clearly not functioning 100%. The email trail from both of my discoveries align with this.
My mother's father died when she was 5, it caused her to marry bad men but she never and would never cheat. I get my black and white thinking about this from her. So what you say may be true but that is really not an excuse. I see this all the time the desire to know why. The real question is does it matter, it doesn't fix her even if you know the reason. It just shows that she is defective and probably not a good choice to continue. The only person who can fix her is her and she has wasted 15 years at this point. Times running out for you to have a good marriage, assuming that was one of your dreams when you were young. You ain't getting any younger waiting for her to fix her 5hit.
I think you should get the timeline and then spring the poly. Thing is if she refuses to take it then that has to be it. You can't back down, unless you want more of the same. I hope she understands she is hanging on by a thread. If she really is, maybe she thinks you are all talk, she was able to con you before. Looks like she just said everything you wanted to hear and then continued acting exactly the same way. She probably knows she can do the same now. You must remember if she can't be honest she is not worth much in a relationship, at least if you want a healthy one. If you look at it that way the ball isn't even in your court.
One more time why are you not telling the man's wife. You are participating in the cover up. What are you afraid of? Where is your compassion for this lady. You of all people should understand the betrayal yet you have no empathy for this woman. This would be probably the most effective way to take some control and power in this situation and you refuse to use it. Again there is that passiveness I keep talking about. I think there is a very good chance you will find out this was a PA, are you prepared for that? Then the question becomes your third child.
If you are smart and move on when you learn to be assertive you will be a good catch for some other woman, you had a 15 year faithful relationship from your end. That makes you valuable. However you should never love anyone enough to let them abuse you. You are responsible for protecting yourself at all times, just like they say it the ring. This passiveness you have shown will make you attractive to the wrong type of woman. And it will turn of the right kind. Woman don't like passive men, the ones that do like them because they can dominate them.
No person in your life is worth your self respect. No matter what you do try to remember that. It's really better to be alone.