Believe it or not, you do have more control than you realize. What I finally understood after my years and years of therapy is he can only hurt me if I let him. It will take a lot because he knows every button to push that used to make you hurt. You have take every "button" out, examine it and either cover it with armor or let it go. The let it go part is actually the hardest.
Learning to preserve our emotional well-being.
My ex wanted to come back and get more stuff out of the house long after the guidelines allowed him to so I gave many of those things away to charity, to people who could truly appreciate them. I will never forget the angry text I got when he saw someone leaving our small town with a piece of our furniture in the back of their truck. I gave it away on Craigslist to a family who didn't have enough beds for all of their children. He felt he should get half of the value of it. When I told him I gave it away what can he say? That sort of thing is only stuff. It's not worth your emotional well-being.
The same goes for money. I was the primary breadwinner and maintained the custody of the kids but did not ask for one cent of support. It is easier to make ends on my own than let him manipulate our financial well-being. What money we did have left I emptied into our kid’s college funds under my oversight. There wasn't anything he could do about it.
If you want to be free, then stop expecting anything from your Ex narc.
With kids there is always the shared visitation, but never discuss anything verbally. The bane of the narcissist existence is texting. Full documentation of everything! Be honest with your kids while never saying anything bad about their Dad. If they come to you with complaints, just comment, "That's your Dad!" The only exception is abuse or neglect, which you document with a vengeance. That is where your armor comes in. You know the phrase "never let them see you sweat?" That was created for dealing with this type of manipulator. You aren't any fun if you don't respond emotionally.
My ex finally said to my one son that I had become a bitch, to which he responded, "Only with you Dad, only with you!"