My wife tried to leave and now says she wants to stay. What should I do?

Several years ago, my wife asked a family friend to runoff with her. Both times he refused. About 2 and 1/2 years ago, she started emailing this same person on a regular basis. The emails became almost daily occurrences and became more involved overtime. During the course of the emailing this other man disclosed that he was going to divorce his wife and wanted my wife to leave me for him. When my wife declined, the man pressed her several times to at least have an affair with her. The two did meet a few times in public places and had a date planned when I discovered their relationship. My wife said she would stop her communicating with this man and wanted to remain in our relationship. It has been a bumpy road and we have both been to individual counseling and marriage counseling. But therapy seems to have made things worse; we swing to highs and then new lows. Also this other man joined our church, married a woman in our congregation and now lives on our same street.