How can I overcome the stress after being verbally abused?

I have 2 children with my ex which we have recently changed to 50/50 custody. (Previously he had them every second weekend). Any time an issue comes up in his time (if they have forgotten to take something to his house etc) it is always on me to solve the issue, and if I can’t I am verbally abused, sworn at etc. it leaves me feeling distressed and worn out. If the same issues arise in my time with them I always deal with it without relying on him. I also get abused if the children have misbehaved in some way, and a variety of other reasons. It is a regular occurrence that I get treated this way over things that should be able to be dealt with in a calm respectful manner. I am aware he is not going to change, so I am trying to find a way to not have his behaviour ruin my day. My reaction can vary depending on how bad the verbal abuse has been. Sometimes I am left in tears, other times I just feel angry because I don’t deserve to be treated this way but I cannot escape this person because he is their father.