Yes, it's something meditation practice can help with. I do a bit of this already but need to spend time, more routinely, building my skills. But it's also something more - and that is 2's point, I think.
It's recognising this aspect of my habitual reaction to things...the problems it creates for me and those around me. And working hard (because it is hard to break the automatic habits of a lifetime) to change how I do things/live.
2, I like your description of how you try to break the reaction cycle. That adrenalin pump is hard to ignore - and it provides a great warrant for flying off the handle.
At the moment, with stbx, I'm going to shut up, freeze (if necessary), and remove myself from the situation. My goal is to avoid being pulled into more drama, and to remain calm and polite in my dealings with him.
Reminding myself that he, too, enjoys the drama of a fight and seems to thrive on my (over-)reactions to his activities, will help me to stay on course to achieve these goals.