I have let her go. I am not dictating anything beyond asking her to not mistreat me or my children. That and I have asked her not to speak with OM in this house because its disrespectful.
Here's another area where you can make some serious progress. This is where you need a boundary! Forget about asking her. When I married my W I asked her to not sleep with anyone except me. Well, so much for that.
This is an opportunity to set a boundary, but I'm not an expert on boundaries.
Maybe something like this: "W, when you talk to OM while living here, I feel disrespected and taken advantage of. If you continue, I will have no choice but to ..." Whatever the consequence is.
And then when she decides to keep doing it, you FOLLOW THROUGH with the consequence.
H: 35 W: 33 M: 11 T: 13
4/10/18: I discovered A and confronted ("BD1") 6/23/18: I moved out 8/31/18: MC ends ("BD2")