The reality is that you can't live your life on ex's terms. As long as you allow ex that power over your life then ex will feel empowered and enabled to control and dictate. Have you read Henry Cloud's Boundaries?
I had to get educated on what boundaries really were. Boundaries are for you, not the ex. You already know you can't tell ex what to do or not do. You can't force ex to do or not do something, your power is in your response. However, what can and does work (though there are limits) is something like this... .
"If you do or don't do ___ then I will do or not do ___."
Examples:
If you start blocking me from our kids... .
... .then I will enforce the parenting schedule, in court if that's what it takes.
If you want extra time for ___... .
... .then I may allow it but with a trade for equivalent time for ___.
When done right "if... .then... ." is powerful. It took me years to figure how to make boundaries such as these.
Oh, and since this would be a change to your behavior pattern, expect ex to flame out with extinction bursts in attempts to make you retreat back into prior compliant, appeasing actions. Ex may never fully accept that you will run your own life, but in time ex ought to realize you're not acquiescing to ex's demands as before and not push your boundaries as relentlessly.
