How to manage partner's angry outbursts?

My (34f) partner (35m) has always had a bit of an anger issue. We've been together 8 years. In my opinion, he gets excessively angry at even the smallest of things, shouts, says mean things about me, doesn't let me talk back because I'm just "being defensive" according to him, and then sulks all day / gives me silent treatment because I have "caused him to be / react that way". In calmer moments, he reflects that he has a lot to work on but he never apologises for being angry or saying mean things. He won't accept my apologies to try and smooth things over, as he says I'm not sorry and love seeing him miserable.

How can I manage this? What do I need to work on to improve the situation? Is there a way this can improve? I really want it to work, and feel such same that we're having these issues. I haven't been able to share it with anyone.

TL;DR partner has angry outbursts and blames me for his moods. What needs to happen for this to improve?