Has anyone dealt with biting or something similar during sex?

Bf and I have been dating around 9 months. Before him I have never even heard of guys doing this and don’t really know what to think. He is 25, I’m 21.

Early in our relationship he started biting me during sex when he was really into it, which was fine because it wasn’t that hard. Couple of times it was really hard. The last time he did it when we were first dating it was bruised bad and looked horrible. I showed it up him and told him he can’t do it that hard, he apologized and said he wouldn’t and didn’t for a long time.

He has been getting back into it more lately. Couple days ago he did it the hardest he ever has. I have this horrible mark on the back of my neck around shoulder. I had to resist the urge to hit him when he was doing it. It is really bad and hurts. I looked at it the next day and got mad. Told him angrily that he just can’t do it that hard. If someone sees it idk what they would think.

He apologized. Said he doesn’t realize when he is really into it and compared it to a hickey. So I have been kind of annoyed with him and he has been sulking, says I embarrassed him and could have just talked to him without being angry. I have never dealt with anything like this so I’m not sure where to go from here. I like semi rough sex as much as the next person but imo it’s just too far. I know everyone has their certain kinks, whatever. He is annoying me saying we will just have vanilla sex from now on. He can do whatever he wants but when I’m in pain for a week after and have to hides bruises/injuries, I don’t like it. I don’t think I’m being unreasonable. I want us to make up but also don’t want him to do it so hard. Has anyone dealt with something like this?