why does my boyfriend do this..?

I've been with my boyfriend for over a year and a half.. I love him more then ever. I don't know what I would do without him.. we go to different high schools and we see eachother over the weekends. But the thing is he doesn't like me talking to guys.. he's very overprotective.. I think a little too protective. I have no friends because he never likes who my friends are. I just gave up on having friends he finds SOMETHING wrong with thwm for him not to like them and not for me to be friends witb them.. if I make a friend and tell him about it he doesn't even listen to what I have to say he just says yea or nods.. I let him talk to girls he hangs out with his friends all throughout the week while I sit in my house all week and do absoultely nothing.. I just don't underatand.. any opinions?..