I agree with CS and the others here. And take heart, confronting the affair does not need to be done with anger or judgment. In fact, you seem like you are very much in control of your emotions (even if you don’t feel like it sometimes).
Not telling your W what you know is already causing its problems as she “knows” something is going on. She can feel the "separation" and I think not telling her will cause further emotional separation. And frankly, it is lying which is the LAST thing you want to introduce from your side of this relationship. Be prepared, however, to be met with a very angry reaction again because the spouses are often embarrassed by their behavior and as a result, they lash out in response. It is VERY important that you don’t respond to that in anger. That you have proof will make her feel further humiliated and withholding that information will make it worse the longer it continues. So your choices as I see it are 1) Never tell her or 2) Tell her as soon as possible.
I find your assumption that she is in love with OM very interesting. I read what you had to say and thought the exact opposite. Listen, it would do you some good to read other threads around here before you make that leap. So many of these spouses that are involved in affairs are oblivious to everything around them. My H also had an affair and the house could have fallen down around him, I doubt he would have noticed. In contrast, your W is still very tuned into you. That’s a bit unusual. I would be very very careful with that type of mind reading at this point.
