This is a very tangible thing you can work on, and it has zero to do with him or anything he does.
So, something happens that shoots your fear/panic adrenaline response - which is immediately followed by anger/rage and an impulse to hit or strike back, either with words or with your body.
The thing to get ahold of is that fear/panic response. Learning every single trigger is almost impossible, since they will shift along with your stress level - you'll get to know them better and better over time, once you can shut down your amygdala and keep it from hijacking your body.
I know I say it til I'm blue in the face, but breath is it. It's all about breath. Shutting down panic is not about soothing, it's not about distracting - it's physical. The best breath pattern I know to start with is in (thru nose) for four, hold for four, out (through pursed lips, like how you'd blow out a candle) for four, hold for four. Repeat. You need to commit to doing it for at least 4 minutes.
Just start doing it - the instant you catch the rising fear/panic/overwhelm...I have no doubt it happens just when you're on here, sometimes - I've seen you post about it. Practice here.
If you are afraid you can't make it for four minutes, when you start the pattern get to a sink and splash your face with cold water while you're doing the pattern, or hold a cold wet washcloth over your face. It will trigger your blood pressure to drop, and that will help. The breathing pattern is doing essentially the same - you can visualize it as purging and re-setting your central nervous system.
Sometimes, it's scary. You'll feel like you need to breathe faster. But you don't. After the first minute, it won't be as much of a struggle. Second minute, you'll think you can stop. Don't. There's more to calm. By the time you get to the end of four minutes, you'll actually be a little bored.
It does not take long to teach your body what this is, and you will notice that you start doing it without any conscious prompting. That's the goal - you get better and better at inserting a response to the panic/fear that will completely short-circuit both that and the following rage.
Because I'm not always great at whipping out my phone as a stopwatch, I timed myself one day on how many in and outs it took me to fill a minute; then, multiplied it. For me, the internal script is "one two three four hold two three four out two three four rest two three four, two two three four....etc. Up to "sixteen, two three four". That's my four minutes.
You should try it, seriously.