The truth hurts.... she knows it and so do you. I'm not sugar coating anything but you know...if you really want it to work and I am sure you have tried in the past...then you may know you are done....what about the chapter in the DB book on affairs? How long has hers been going on for? Also I have read that the more W hangs out with you and the more she stays in contact with you....the more this is going to piss off OM and he will start to show his true colors....what are you going to do? Are you separated now?
Maybe a separation is in order.....fast and clean....her butt out the door if she is so happy...make it legit though.