You are not in control over your W. You are only in control over you.
Read Divorce Remedy. Read what it says about infidelity. I don't know if your wife is also exhibiting symptoms of Mid-Life crisis, but that's also important information.
In my case, my H definitely wanted to have his affair partner and me, especially at the beginning. He bravely declared that he didn't care who knew about it, he was certain that he'd found the way that most people should live. It was complete crazy talk. He knew I was against the affair, and I established some pretty weak boundaries, but boundaries nonetheless (no texting her in front of me, no late evenings after work when he should be home with his family).
The fantasy is unraveling bit by bit. It takes time and patience and it's utterly awful. Detachment helps a LOT. He also is recognizing, slowly, what he stands to lose. He has actually told me that the grass is NOT greener on the other side. (I don't bring up the relationship anymore - just listen when he talks.)
