When your child goes to have unsupervised contact with the parent who is abusive..

[MysticPeg1]

How do you deal with it?
How do you detach from it mentally.
I'm also interested to know if you have no coparenting relationship whatsoever with the other parent, how do you feel knowing the child you share is with them.
I just want to learn some coping techniques.
I'm keen not to project my anxieties onto my child.

I think you would be less anxious if you knew your child knew enough to know WHEN that parents behaviour was wrong. Very important to start educating them from a young age how to spot bullies and that it is never our job to try to change them because monsters dont change. Of course, never name names. But hopefully they will make the connection and by the time they hit their teens, they'll be able to tell them to bugger off. Power comes from knowledge, so make sure your kid grows up knowing how to spot nasty people, then they'll never find themselves in that predicament.

Kudos to you for being able to stand it though op.
Personally I'd up and move accross the world and not leave a forwarding address rather than let them spend one minute with the child. But obviously, there can be legal ramifications for that so I wouldn't advise it.

Are they old enough to use a phone so you can text and check in with them?