I'm glad you're venting here.
Writing letters is a good way to sort out your feelings and make sense of things.
It sounds like you both have the same aim but have different paths of getting there.
My husband gets really angry and yelling and punitive as well. He takes every challenge as a personal attack and can't seem to recall that he too likes to challenge authority and rules.
He grew up in a very punitive, aggressive household, where nothing was explained, it just WAS and you got in line or got hit. He didn't like it, but he feels he "turned out okay" (which is debatable if you ask me), so why not go with tradition. The more at the end of his rope with his own life he is the more this seems to be true.
At some points I prefer him to detach entirely and let me take over, because what he is doing is not safe in my POV, to which I usually hear I am being dramatic.
I think it would be a good idea to discuss this issue. It seems your DH has a need to feel in control, especially if the rest of his life is spent working in oppressive conditions as you describe. he does deserve that. Everyone deserve autonomy and a sense of control over their own lives. But his two year old cannot be controlled and neither can you. This is a serious issue if he is going to insist that he deserves to control YOU and YOUR actions (you plural, not just you, Hablame)
Ya know how we redirect and distract toddlers? I have found this technique works well with adults as well. Your husband is requesting you and your son to fall into the domain of his power, because he pays the bills and he works all day and he is the man. Just because he works hard to provide a SAHM lifestyle for you and his son, doesn't mean he owns you or can call all the shots. He wants to feel in control, but he is going to HAVE to find another way to do that. Perhaps you can help.
Let him control in ways he can. He can pick the dinner, he can pick the movies and TV shows when he is home, he can control the bedtimes, and he can go out and control his own actions some times...
There has to be another way of expressing his autonomy without being a tyrant to a 2 year old...ya know?
It isn't easy, but I agree with your husband about one thing. You DO both have to be on the same page about discipline for it to work, no matter how you approach it. Even if you got a divorce this would still be true. Co-parents need to parent from the same place or it really won't