My advice to you is not to sit still while this affair is going on. If need be follow her or tape her phone calls to find out who this joker is. The chances are that this man will run like hell once her finds out that you know who he is. If he is single he is not going to be interested in getting saddled with 3 children and if he is married he is not going to leave his wife and family. A woman expects her man to fight for her. If you go along with her affair as if nothing is happening she will loose any remaining respect for you. I would recommend that you use a love tough approach that you can read about in the book by Dr.J.Dobson "Love Must be Tough". You cannot tolerate her behaviour and expect her to respect you. The reasons that she has tried to keep this affair secret is because she knows the negative consequences it will have on her marriage and children. Plan A will only work if she stops all contact with the OM. Best wishes..max