You will find that many ow/om are very damaged themselves. They are usually extremely insecure and even more messed up than our spouses. They are generally manipulating and controlling. (Threatening to jump out of a moving car...)
Don't stick your head too far into the sand concerning the ow. Sounds like she may go to great lengths to keep your H. Remember if she's done this with your H, her character is probably not the best. If he's sleeping with her, he's sleeping with everyone she's ever been with, and then possibly passing that on to you.
You must protect yourself, you have a little one that needs you. Especially since daddy is aboard the crazy train.
Hang in there. This all will become more clear as time goes on.