I have been in a relationship for 2yrs with my boyfriend i need advice on how to handle this?

I'm a 21yr old girl. I have in a relationship for 2yrs with my boyfriend. At first it started out ok, we were in love did things together and never argued at all. He became my world and I ignored my friends because of him. Later on in the relationship my friends told me that I lost my personality. I was a cheery, sociable and happy go lucky person. So after a while he went overseas to visit his Parents for like 7months. During that time I regained my old personality, because it he never called me or emailed me at all. So later on i decided to break it off because i felt under appreciated. He came back suddenly and we got back together and then he insisted we move in together or he can't be with me. My friends adviced against it but i still went on with him. We moved in together. Since then we have been having major arguments and he has even hit me. He is always saying am wrong. He is an introvert type my exact opposite. Even when i talk normally he says am loud but i talk thats my normal. He doesnt respect anyone as he thinks he is a 'god'. I recently got a new job as waiter in a restaurunt. My boss has this family type of relationship with his employees. So i truly admire him. My boyfriend HATES him. They have met and almost even got into a fight. I dont talk about him at all to him but because of My boss' nature he thinks i am want to sleep with him . Now we are arguing a lot more than before. He threatens me everytime, saying that he will ruin me if i ever try to move out. My friends and his friends both have adviced us to break up. We had an intervention by one of our friend who adviced us to try and be considerate to each other feelings and also to try and accept each others quacks rather than being controlling. We tried for about a month and it was bliss but later it reverted back. We turn small arguments to big ones.We have been like this for several months and now he blames it all on me. Now again the threats are back. what do I do?.