As you can see Joe is also new to DB and is learning on the fly.
Setting boundaries are about what you are willing and unwilling to tolerate. (protecting you)
The key word is you. You can't control another person (your wife). You can't say to your W "you can't speak to the om on the phone". She is an adult so she can do as she pleases.
However, you can say "W you can contact OM while in the house if you would like, but if you continue to disrespect me and our marriage in our marital home, I will ....................
You have to fill in the blank with the consequences. There has to be consequences to a broken boundary and if broken they have to be implemented.
******* BIG NOTE******** DO NOT set a boundary unless you are willing to go through with the consequences if broken because it will just make you look weak and make matters worse.