"Do I insist on this boundary? I don't want to make it an ultimatum."
Yes. It's not an ultimatum. It's what you can tolerate and you're not controlling her. She's more than welcome to talk or text OUTSIDE the home but not in the one place where you feel safe.
"How do I enforce it? Take away her phone and credit cards? I'm trying to earn respect, but I don't want to come across rash, pressuring, vindictive, or punishing."
That would be controlling her. If she insists on calling the OM on her cell phone, then stop payment on the phone if you're paying for it and tell her to get her own phone. Same as credit cards. If she's using them to pay for things for the OM, then don't pay for them. Simple as that.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.
