I'm not going to let my bf buy games that his friend wants him to buy to play together
Why are you putting up such a fight against it?
He deserves it for wanting to play games more than spend time with me.
It is important to spend time together in a relationship.   It is also important for both sides to set healthy boundaries.    Being too controlling could drive him further away from you to the point where the relationship might end.
I'm going to follow everyone that he talks to on twitter and tell them how much of a bad boyfriend I have. I'm going to make him suffer by not giving him sex.
It sounds a little bit extreme to act this way. I think that it is wrong to tell him he cannot get the games. It is not okay to control other people's behavior.