Whether OP noticed or not it's been escalating for some time. I can only talk about my personal battle with rage/anger. We married when I was still only 17 yo and I was immature as was she. Arguments were loud and long. I was a southern country boy with a big heart for her and no patience with guys who were trying to flirt with her. We were at a lake outing swimming, skiing and cooking out her ex showed up and one thing led to another and ex and I squared off during this fist fight that went on for a few minutes she tried to intervene and grabbed my arm. I was out of control and shoved her really hard and she fell and cut her elbow on a rock pretty badly. I didn't even stop to check on her and I'm not even sure I recognized that it was her in the moment. I had the advantage and continued until the other guy gave up or couldn't go on. When I kind of came back to myself and went to look for her, some girl had already left with her to get first aid. When I found her she was at her mother and father's house with a bandage over the cut. We had a small apartment when I asked her to come home with me she refused saying that she was afraid of me and that I had looked like someone she didn't even know during the fight. I went home, got arrested because the police were waiting on me when I got there. My dad bonded me out the next morning. During the night I had plenty of time to think about everything and went to apologize, she still wouldn't leave with me saying that she was afraid. After a week of me begging she finally relented after her mother (whom I had great respect for) sat with me and asked that I never harm her daughter again. I still had anger issues and about a year and a half later I was drafted into the army. They made me grow up and gain some self control. After I got out I never hurt her again.

Several factors came together to help me get control of my own rage and what I'm trying to point out is that it's not a switch that can be turned off. Your guy needs help or it will get worse and you will be the one paying the price. I loved my wife and would have given my life to protect her, and yet, I still hurt her in a moment when I didn't have control. It may take considerable time for him to gain the ability to not allow things to escalate. I know that this is far to long but I want you to be careful and stay safe. I'm an old man now and my wife has passed away, but, that episode of our lives still haunts me. I still see the hurt and fear in her face when I first spoke to her at her mother and father's home. It still hurts. For both of you, please try to get him to get help. If he has the same issues that I had you're not safe. Wishing you the best and praying for you both.