I just recently found out about my H and what he was doing behind my back. He was sexting with other woman, had profiles on sex search websites, and what got him in trouble was he started asking my sister (she is bisexual and open about her sexuality and he knew it)to have a 3 some and one on one sessions with her (She contacted me immediatly and together we trapped him into admitted that he was cheating on me and having 3 somes with other women),
Anyway my point here is, that part of the allure of the affair, I think, is the possibility of getting caught. Kinda like going parking, you always wonder if someone will catch you but it's fun to do it anyway. You need to confront her and get it out there that you know what is happening behind your back, how you feel about it, and maybe what will happen if she does not quit. Let her know that you do not agree with an open relationship and if that is what she wants then she will lose YOU in the procces.
I did not give my H an opportunity to come clean or to give me his side of the story before I filed for a D and he was served. He has since then voiced how I 'betrayed' him for not talking to him. (Oh well he betrayed me)
If you never say anything to her about what you know then it will eat at you everyday and it will be you that hurts more than she will. If you let her know that you know what is going on and she sees the pain that this is causing you, then it is her that has to live with the pain of it everyday of what she is doing.
Don't let her think that she is getting away with the allur of the affair.
Me-31 Him-28 D1-9 D2-6 Married 5-06 Seperated 12-07 He filed 1-08 Reconciled 4-08 D dropped 7-08 Bomb dropped about H's activities outside the marriage 4-21-09 Filed for D 4-28-09 Trying to make a go of it 6-09