Buster, Moving back in will SHOW her that you are not about to abandon your wife or your child. Personally I think that it will be brutal, you will probably see her behave in a way that you never imagined she could be, but I encourage you to do it. It will also show the OM that you arent giving up on her. If you really want your M then its always worth it. Hopefully she wont take your baby, but at least you will have made a concrete effort, and I think that it will be a display of your commitment to her and your personal integrity.
Good luck, this is so hard.
I guess I gave the wrong finger to the wrong man...