After ending a relationship, you and your co-parent will have to make literally thousands of decisions regarding your children's upbringing. While many parents can put their feelings aside for their children's best interest, you can't rely on a toxic person to come to the table and keep the kids' best interest at heart.
Any chance to communicate with you is an opportunity for them to torture and punish you. You've tried to set boundaries, but setting boundaries with a narcissist is a recipe for failure. Unless you know how to make your communication transparent and your boundaries rock solid and enforceable in the court systems.
Perhaps more important, you need a dispute resolution practice so that you're not being dragged in and out of court every time your ex wants to be difficult. This course costs about two hours of an attorneys time which you are guaranteed to save in the future with some deliberate planning to be able to co-parent with your ex without allowing their toxicity and narcissism to impact you and your mental health.
Find peace and freedom with this 10 hour course with over 100 pages of accompanying PDF pages.