Why is my boyfriend so controlling?

My boyfriend and I have been together for quiet a while now and he’s always had a temper and I had asked him why he would curse at me and he had said its because he has an anger towards me and I asked him why and he said he didn’t know…but for the past few weeks he’s been getting really aggressive with me like one time we were sitting on the couch an he got angry at me because I didn’t what to talk to him about my bad relationship with my dad and he got up to walk out on me and I held his hand and asked why he was going and he hit my hand away and sat back down…I got really scared…I was speechless because I thought he was going to beat me by the look in his eyes and he pushed me and said talk to me…I didn’t know what to say or do so I just told him sorry…then we went out another time but I wasn’t feeling well and he knew that and we were crossing the road and he got angry and started to yell at me for walking too slow and people were watching…it was so embarrassing…another time was when we had made plans to go my best friend’s party but he couldn’t go because he had work but I said I was going once my mom gave me money to do my hair and he went off on me and kept yelling at me until I started to cry but he still wouldn’t stop…he kept saying crying not going to save you then he called me the day after and said to walk over by him and I asked why because I knew he had work and he went off on me again and said when I tell you to do something do it and cursed me and hung up so I started to walk over and meet up with him and his mother in a car and they made the car stop to pick me up and he shouted walk quick girl and his mom said don’t talk to her like that and when we reached home he put me to sit and locked the door and he sat down and turned to me and said when I tell you to do something…what you supposed to do? and I said just do it and I was sorry because I thought he was gonna hit me…I’m 17 and he’s 19 and I don’t know what to think or say The only thing he has done that’s physical is grab me or push me…but I’ve known he for 9 years now and we’ve been in a relationship for a year now I really love him and he treats me great when he’s not angry…what do you think?