JonathanH...I had an affair...it ended my marriage...And in hindsight...thats why I did it. I didn't stay with the guy. He was a bit like curious describes himself...he was a player.
I agree with you about feelilng angry towards curious, he took advantage of another mans plight. BUT...he is right in a lot of ways. (not about joining a swingers group though...)
I am not your wife so can't say for sure why she did what she did. Sounds like infatuation to me...lust even. The fact that she told you about it and hasn't left either means she is selfish, and just wanted to relieve her conscience...or...she wants help to stop this behaviour and wants to save her marriage. I didn't want to talk about it, I was ready to walk, and did.
I agree with the suggestions on here about marriage councelling, you need to find out why she did what she did.
Just a mention of one thing you said that stood out to me...you seem to treat her like you're her mother. I know it must be because you are at home when she isn't so you make her lunch/dinner? Do you do everything around the house? Don't be a doormat!! Woman don't respect doormats. I am not saying that to be unkind, because I can see you do this to be loving and I think that is lovely. But, I feel much the same about stay at home dads. All the stay at home dads I have met have been like wet fish....Yuck...If you want to keep a woman, you need to be a man, helping is great, doing it ALL is not. That is just my taste mind you...some women like that...