I think I am being manipulated by one of my best friends. What should I do?

I have a friend group of 3 people. One of them is really nice to me, like a sister. The other one, who I will call Steve was also one of my utter best friends. I am not in love with him, but i loved him like a brother. He was one of the only people that told me I was awesome and his best friend and made me feel very special. But only sometimes, because often if I got a bad grade, or did something he didnt like etc, he would yell at me, calll me dumb, stupid and useless. He would always get me down. But after our fight I always went back to him, even thoough he never apologised. One of the reasons was because i loved those rare occasions when he made me feel special and the other was that i didnt want my other friend (who he treats nicely because she does almost everything he wants or orders her to do without question) to choose between us. Now he was REALLY mean to me about a tiny thing that wasnt my fault and it really hit me very very very hard. At the moment i am ignoring him, but he is trying to make me hurt because he really gets a kick out of my pain. I dont want my friend to have to choose between us. Is he manipulating me? And shopuld I go back to him or distance myself from him completely?