What I meant about talking (Not confronting) the OM is that his email to your wife made it sound like she was the pursurer and he was wavering. Just a man to man talk about his side of whats going on and its impact on you and your child might just make him even more unlikely to get with your wife. Work on his conscious a little. Thats what I getting at. If he steps away he incentive to leave might go as well!!
