My boyfriend and I hit each other?

OK so my boyfriend of almost two years and I sometimes hit each other. Last night he just sort of slapped me on the arm so I did it back.. Things escalated and he bit me on the head and it really hurt. Things like this happen a lot and it starts by him hitting me either jokingly or for no reason but he always does it harder the next time and I get mad so I try to hurt him back. He is twice my size and hurts me way more than I can hurt him. it usually ends by him hurting me pretty bad and then we just stop talking for the night or he gets high and ignores me. Other than these times we are totally in love and have what onlookers would think is a perfect relationship. Also, he grew up in an abusive home so I think maybe that has something to do with it? I don't know. Someone help.. please?
My boyfriend and I hit each other?
Post Opinion