I knew there was an OM from the very first post. It was just so textbook. He's still in the picture by the way. Her actions prove it. You have zero chance of fixing your marriage as long as there is an OM in the picture. First, dig and confirm an OM. That should be pretty easy, she's basically flaunting it. Second, 180 her. You can look that up.
Don't be passive and do not be her doormat. Nobody respects a doormat. She'll see you as weak and unattractive. Be strong and firm with her and you might save the M. You have to be the leader of your house. The king of your castle. If you're not, she'll find another king. She currently is auditioning for your replacement. Don't be a spectator for that.