I didn't understand why he didn't want me to meet his family

I've been dating this guy for nearly a year. He's Italian. His family is actually from Italy. He hasn't let me meet his family and at first I thought it was because there might be another girl. When I asked him he said no, but he's sure I won't want to be with him after I meet his family. I said of course I will. I just want to meet them. So we had dinner two weeks ago and it honestly went really well. His mom was so sweet, his father was cool. His brothers and sisters were funny and great to me. We had a great time and they invited me for dinner the next week, which was last week. So we went over there and everything was fine, but there was a lot of tension. Soo. His brothers start arguing. They are speaking Italian so idk what they are saying. The only thing in English I heard him say was "Your wife is a whore!" His father is also talking in Italian. His one brother then pulled out a knife and stabbed right next his other brothers hand on the table! I screamed! Everything got really out of hand real fast and now the brothers are fighting and a gun is pulled out and everyone is speaking in Italian! My boyfriend and his father were trying to calm down his brothers. And one flipped over a table. No one shot the gun thank God! Afrer like 45 minutes everyone calmed down and my boyfriend took me home. He said "This my family." I asked what they were fighting about and my boyfriend said "Its not important. It will be something else next week." I'm like how often does this happen?! He asked if I still wanted to be with him and I said yes. Just maybe dinner with his family once a month instead of every week. It was definitely scary and I don't understand how his brothers can fight like that!