Need advice for approaching DM about a problematic player

I'm in a weekly RPG group that has had a couple people come and go, but it's been us main 5 for a while now: me, another woman, two men and the DM (who is a man). The other woman player has now brought her boyfriend to our games.

I knew him from when he joined our group before. He seemed okay but didn't enjoy the system so he stopped coming.

Now we have recently started a new system and this is when he started coming again. Almost from the start, he and I seemed to butt heads a little. At one point, we got into a very heated argument about D&D vs. other systems and he raised his voice and got very angry. He scared me.

Since then he has had a couple of loud outbursts but not quite as bad. But, its getting to the point where I don't really want to go to game night. He hasn't threatened me directly but I do feel threatened.

My issue really comes down to what do I do? I really like this woman as a friend and it's hard for me to make friends. I don't want to call him out at the table in front of everyone for fear of his reaction as well. I don't necessarily want him to stop coming, but I don't want to be afraid of him having another outburst. The DM and I are on good terms, I'm just not sure how to bring this up to him. Do I ask him to ask the problematic player to tone it down? Or ask the DM to run interference if he starts to get loud again? There is also a chance that he will quit the game in the next two weeks, since apparently D&D is his preferred system. I really don't want to just stop coming as these games are my refuge from being a SAHM.

Any advice?

Edit to add: talking to his girlfriend is my last resort. When he has these outbursts, it seems like she doesn't notice or doesn't want to acknowledge his behavior. If I ask her what's up, she may reduce contact with me and "choose" him and I do not want that. I am leaning toward messaging the DM so he can interfere during the outbursts and my name stays out of it.