We learn about relationships first and foremost from our parents; look at what yours taught you. They taught you a shedload of damaging lessons and this man is not the first abusive boyfriend you've been involved with either. Its no coincidence that either of these men have been or are involved in your life now; your childhood set you up to tacitly accept abuse and other ill treatment because its familiar to you. Your parents abjectly failed you as a child. BTW are they still together?. It would not surprise me if they were because on some level they both get what they want out of their dysfunctional and otherwise abusive relationship. They never bothered to show you what a mutually respectful relationship is like and you still do not know what one of those is. No-one ever bothered to tell you up till now that the only acceptable level of abuse in a relationship is none.
He can and does control himself around other people so he does not need anger management. He has a problem with anger, YOUR anger, when you call him out on his behaviour. AM courses as well are NO answer to domestic violence which is what you're describing in all your posts.
He may well not have punched holes through the walls but the fact that he has punched walls at all is bad enough. He's sending you a message; first the wall then at some stage if he decides that is not enough for him it will be you. Your relationship was really over the first time he threw a punch at an inanimate object like said wall.
You need therapy like yesterday frankly starting with your childhood but a good place to start for you would be Womens Aid.
You cannot act as either a rescuer or saviour in a relationship; neither approach works. You are not a rehab centre for this badly raised man nor should you be acting as such by trying to "understand" him. You are in a destructive cycle of codependency with this man and now you seem further stuck on the sunk costs fallacy.
People get bogged down by focusing on their sunk costs.
There are two ways to understand this process, both involving avoidance. One is an avoidance of disappointment or loss when something doesn’t work out. When a relationship doesn’t succeed, especially after a long period, especially after many shared experiences and especially after developing a hope that the relationship would be a good one, it is a loss. It is a loss of what might have been and an acknowledgement that a part of one’s life (six years in your case) has been devoted to this endeavour.
Another angle to evaluate is that focus on “sunk cost” creates a distraction from one’s inner truth. The sentence often goes like, “I’ve already invested to much, so I can’t notice my thoughts and feelings that are telling me to end or change this relationship.” This is a type of insidious defense against noticing yourself. You enter into a neglectful relationship with yourself which divorces you from your inner thoughts and the quiet feelings that might guide you in your life. In other words, thinking about what already has been may prevent you from deciding what you want your life to be.
You've had six years of him; do not waste any more of your late 20s like you are now because life will not wait for you.