How can I stop my friend from being too protective?

I cant hang around anyone without my friend trying to fight somebody. If i'm play fighting with someone they cant touch me without him giving them a mean look or saying something. He's like "if you touch her, i'll beat your @ss." If I do get into a fight with someone he wont even let me fight for myself. I have told him nicely to stop and if I try to be mean he wont listen. I cant hang out with boys or he'll threaten them. I love my friend and he's like a brother to me so I dont want to be mean and tell him to stay away from me. He has saved me a few times from some bad situations, but I dont want him threatening people all the time. If i'm arund my boyfriend he'll watch us and if my boyfriend starts an argument he'll jump into the argument. He almost got into a fight with the guy I like because he said something bad about me and I really dont care about what he said.He treats me lke his little sister. How do I tell him to stop being protective when he wont listen?