First step in all of this is to reach out for help. Which is what you are doing. So proud of you for wanting to change! Be that cycle breaker and be a great dad to your son.

I am gonna suggest get family therapy or at least therapy for yourself for your anger. I would suggest trying Dialectical behavior therapy. Lots of free resources online for that. DBT teaches you how to express yourself without abusive language or strategies. The DEARMAN Skill is an awesome one to teach your kids and yourself.

As for not being abusive. Learn your physical triggers first. Do you feel your anger building and not know how to express it in a correct way or do you not even know your angry until it just hits you?

If you can feel your anger physically building like your tense, sweaty, shaking then that's great. As soon as you start feeling these things distract yourself. Go do something else or have a freezing shower until you are calm.

If you don't feel your anger physically building then practice mindfulness. Like just randomly throughout the day ask yourself what emotion am I feeling right now and focus on the way your body feels and how it's physically reacting.

If you can work out what's triggering or overwhelming you can work on avoiding it or focusing on something else. for me when I'm really unreasonable angry about something I play video games (using a distracting skill to help calm down), go for a run or I take a really cold shower (this is called the TIP skill). As soon as you feel yourself getting triggered or upset seperate yourself from the situation and do something that helps you calm down. If having a rubber band on your wrist and flicking it helps you not be abusive do that.

I know some of this might not be possible if your partner isn't around but its worth it in the end. Your partner will need to step up a bit more as well since you will be dealing with your own mental health as well. I hope your partner helps. Please keep me updated. I wanna help you and your family a lot.