Identify the boundary you can control
Say what contact you will respond to, what you will not participate in, and what you will do if the line is crossed. A boundary is not an order controlling the other person's private life.
Separate logistics from emotional contact
Create one channel for children, housing, bills, belongings, or pets, and keep it factual. Set a date to review temporary arrangements instead of reopening them every day.
Use stronger protection when agreement fails
Block, document, involve a neutral third party, or seek specialist and legal support when contact becomes coercive, threatening, or prohibited. Safety takes priority over mutual closure.