You can't control the other parent. But you can choose your response. If you can diffuse the urgency and your need to be right, smart, witty, or even a jerk, you will go along way towards lessening the drama and making things easier for both you and your kids.
Yes, divorce is hard. Trying to whitewash every single detail of a co-parenting relationship in some fantasy land haze would be of benefit to none of us. I am committed to owning my part in the divorce, always. And I am hopefully clear on my self-awareness when it comes to my own struggles with money, depression, communication breakdowns, and disagreements with my ex-wife.
During my failing marriage, I got very good at listening for the sirens of destruction (I had done something wrong) and looking for an escape or some heroic journey to fix the problem. Both in my marriage and in this relationship, that was not the right approach.
There will be time for anger. There will be moments when anger is the only way you can find to stand up for what you believe to be right. But the rest is up to you.