Why does he act like this? Immaturity.. or something more?

My boyfriend and I have been together for almost 6 months. He treats me very well.. except for when we are arguing. I feel like he plays mind games with me, or maybe I am just reading into it too much. Heres an example of what happened yesterday. We were arguing about something and he was being hurtful. So I was telling him that he is hurting my feelings and I dont like when he says those certain things to me. I was calm and talking normally and he kept cutting me off. I asked him to please let me finish my sentence and he kept saying no and cutting me off. I told him to please stop being disrespectful, and he said to me.... you think im being disrespectful, fine then i WILL be disrespectful.. and he walked outta the room and slammed the door. Later on I tried talking to him again and I said something like.. why are you being so mean to me right now? He said... you think I am being mean? fine then right now i WILL be mean... He does this to me all of the time. Is this immaturity? How can this stop? Or am I the one doing something wrong? Advice? thanks