What you have to accept is that you have no control over her behaviour. She is an adult with the right to make her own decisions. She made the choice to marry you and can make the choice to di vorce you if she unwilling to stay in the marriage. Howerver, you have also the power to stay or leave a marriage if you do not agree with her behaviour. IMO,the way to stop this affair is to let know in no uncertain terms that you will not stay married to her if she continues the affair. I would show her that you are serious by cancelling all joint bank and credit card accounts, joint health policies etc. I would also hire a P.I. to get evidence on her affair. I would tell the OM's employer, his gf, your wife's parents etc as to what is going on. I would make lots and lot of noise. Once an affair is under the spotlight it stops being so appealing. Your wife needs to see that you are serious about divorcing her than standing by while she is in an adulterous relationship with the OM. That is when the fantasy balloon is going to burst.
