I am in the same sit. but the female version. I feel the absolute same way as you do. The thought of my daughter with the OW sickens me b/c she had an affair with my H. She knew he was married just as in your case with the OM. It tells you something about their character and morals...they have none. I have gone to the point of asking in the separation agreement that my D is not to be around the OW but it is very difficult to enforce this and you need very good reason that your child is in some sort of danger if they remain around the OP. The likelyhood is that your WAW probably won't end up with the OM and it will all fizzle out shortly. So i wouldn't put a lot of effort into worrying about your D being with the OM.
M=42 H=51 Common-law 6yr Children: 11yr old daughter (previous marrIage) 6yr old son Bomb dropped January 2013