Who decides how sensitive you should be, and what 'too much' or 'too little' would be? What authority do you answer to, about this? How do we know what the 'correct' level of sensitivity is?
Regardless of the behaviour, if you don't like it, you don't like it, and anybody who cares about you will respect your feelings. So, if it makes me feel sick every time I see my partner eat a strawberry yoghurt, then I say so, and my partner, who doesn't want me to feel sick, will amend their behaviour, in order that I don't have to see them eat strawberry yoghurts. It's not about whether the behaviour is 'abusive' or not; it's about your feelings being respected.
Don't spend time with people who don't respect your feelings. That's all you need to know about boundaries. Get away from this guy, and stick to that one rule, and you will avoid all abuse and shit relationships for the rest of your life. You will give your son a strong education in how to have a happy life, and to not be treated like crap. You will give him agency.
When did you learn to dismiss your own feelings? Usually it comes from our parents. Did you have an absent/addict/ill parent? Fighting parents? Parents who were overly occupied with a sibling? Somewhere along the line, you've felt that nobody was taking any notice of how you felt, and given that you couldn't leave (because children can't just walk away), you had to take no notice of how you felt, either. Your parents will have conditioned you. Don't pass the same conditioning onto your son ('I feel shit, but I have to stay here')