he pulled my hair in an argument. is that normal?

Hi girls, so I have a situation here. Me and my boyfriend are airbnb hosts and this morning our guest wanted to heat some bread and have coffee in the kitchen while I was cooking my boyfriend's lunch. I lived in Italy before and this guy was from Italy too and wanted to go to UCDavis and I did a visiting period there 2 yrs ago, so we starting talking about those things while I finished preparing my boyfriend's lunch.  I was done in the kitchen and went upstairs and tried to kiss my boyfriend and he told me he was mad at me because I was flirting with our host. To my view, I wasn't flirting and had cero interest in our guest, I was just having a conversation. But he told me that he did not saw it that way, that I hurted his feelings for not understanding that I was flirting to his eyes. He left to school in the morning, and I thought of that all day. I felt bad for that and for not understanding that to his eyes I was been disrespectful, So I made him a pie (he loves them) while he wasn't home and thought of what to say to apoligize. He came home and did not wanted to listen to me. He started yelling at me and he got so mad that he pulled my hair. Everything got out of control after that from my side because he scared me a lot by getting physical. Is not the first time he does that to me, one time he opened my lip because he got mad in an argument. All couples have problems and I understand that, and I know am not perfect but am really scared that he won't change. That he will just get worse with time and that if I marry him he will even get more possessive and one day hurt me badly. Am sorry about my long story and I should mention too that I get very very emotional with arguments and cry easily to, and even have panic attacks by just seeing him so angry. I need an advice, is this normal in the american culture? Did I really crossed the line and disrespected him that bad that he needed to get physical?! A part of me tells me is not right and We should end the relationship because we love each other but our love is sick. What should I do. We live together and I do not have family in the State. How do I talk with hom about this? How do I make him understand me too?