Hi, batchel.
I think your best bet is to detach as much as possible, given the current situation.
It will become easier in time as you define in your head what is acceptable and appropriate regarding the soon to be ex.
I forget. Are you able to get to Al-Anon meetings?
I found contact with people there very helpful for my clarity and serenity.
Assume you are going camping "for the kids?"
Or are you concerned about something else?
As time goes on and, hopefully, you and the ex can work out a co-parenting situation, you should be able to do less and less of this.
I don't know why your ex is angry.
Please keep yourself, and the kids, of course, safe.