OP - you could be talking about my DH and his parents. DH had a a lot of anger issues and would explode. Never violent of physical towards people, but very intimidating and unpleasant - throwing things etc. And it wasn't just to me - he was famous for it in his friendship group and had had a few (less bad) situations at work.
Over time, I came to realise that his parents had absolutely NOT made any effort to channel or prevent these outbursts. They told the "funny" story about how he once had a John-McEnroe-style temper tantrum while playing tennis on holiday... so they had to buy him a new tennis racket. He was also the golden child - could do no wrong and was indulged and allowed to do whatever he liked, whenever he liked. On one occasion, he was being a complete ass and had something 100% wrong and his mother, who was there, told me that yes, he's being ridiculous but I should let it go as it's "easier".
We were engaged because of course, these incidents weren't constant. But there had been a couple and then he went absolutely ballistic over something completely stupid and nearly hurt an innocent bystander as a result. And I realised that this had to be a deal breaker. I left the house and told him I wasn't coming back and we weren't getting married if he didn't get on top of this.
He had a lot of therapy and support and he did the work. And it wasn't easy. And it took time. But he DID it. Needless to say, a LOT of his issues were to do with his family and the way things had been when he was growing up.....
You absolutely do have to give him the ultimatum and you absolutely do have to stick with it. The only way he will change is if he sees how important it is and is willing to put in the effort.
PS I strongly suspect that he was, in effect, borderline (or properly) abusive in previous relationships. Using his anger to get what he wanted. Not because he was some manipulative bastard, but because on some level he'd learned that if he threw a tantrum, things went the way he wanted them to and at least one girlfriend put up with it rather than eventually doing what I did. But it's why I often come on threads to point out that abusers aren't always horrible horrible evil people, but that doesn't change that their abuse is real.