I'm so frustrated that I cannot make him see.
If you've not been on this board before, that's okay. We'll share our experiences and what we did to address problems like that. Most of have faced your dilemma or aspects of it.
I see you were never married to your ex but do have court orders in place. Court orders need to be written with terms that protect both you and the children. Beware of terms or processes that make you deal directly (and endlessly) with the ex. At some level you know you can't reason with someone who won't listen or constantly rewrites the communication script (manipulations, guilting, demands, ultimatums, etc). Yet from your description of this recent incident, you are doing exactly that, trying to reason with someone is can't or won't listen to reason.
Sadly, if you continue expecting reason from someone seriously disordered, this frustration and sabotage will continue.
I'm sure others will respond soon to include what's worked for them to avoid these no-win situations.
My thoughts are that you first need to keep your distance from him. With past DV behaviors and court action in response to them, getting back into range of his personal comfort zone is a virtual invitation to let him fall back into past abusive behaviors. Can exchanges be done at public or neutral locations? DV is less likely to happen in public scenarios. I did exchanges at sheriff parking lots for the first couple years, then we relaxed to restaurants or gas stations.
Second, arguing, appeasing or acquiescing are all poor boundary or negotiation tools. You already know being nice or reasonable, even if it works for a while, will fail when the extreme moods and perceptions are triggered. Frankly, while you don't have to be nice, you do need to never incite incidents by getting frustrated and yelling or whatever. Try to imitate court and other professionals, talk and write as emotionally neutral as possible. A truism sometimes commented here,
The one behaving poorly seldom gets consequences and the one behaving well seldom gets credit. Of course you don't want to be seen as raising the level of conflict, but stop trying to appease or demand with him, generally it will fail sooner or later. Focus more on practical Boundaries.
Third, he's an adult, he needs to own his consequences. You'll never "fix" him, so change strategies. Follow the approach by family courts, they deal with behaviors and behavior patterns. During my 8 years in and out of family court on custody with parenting issues, it never tried to fix my ex. Actually, the last time in court the decision noted that she needed therapy but didn't order it since it speculated she might not be able to afford it.
