Ox, the boundary thing is the ONLY thing you have control over. And it is NOT controlling. Well, it is controlling YOU. "Wife, if you contact OM in this house today, I'm going to stay with Joe for the night. You can take Son to his piano practice by yourself." Or "Wife, if you bring your special phone with you to see Older Son this weekend, I'm going to rent a separate room to stay in and see him on my own time and rent a car to get home because I don't want to spend my weekend with a woman who blatantly cheats in front of me."
That's a boundary (don't contact OM) followed by what the consequence will be (loss of you for the day). It's then HER CHOICE if she wants to contact him so badly that she'll risk facing your consequence. That's not you controlling her at all - it is you protecting YOURSELF.
