Boyfriend problems, What should I do?

Okay so I'm 17 and my boyfriend is 20. I go to school, and as soon as I leave school, I go to work. My boyfriend does not go to school or have a job, and he always wants to be up my butt no matter what. He comes to my work all the time to pretty much see what I'm up to and make sure I'm not flirting with other people. When he's not at my work, he is at MY family's house... after telling him countless times that if he didn't get a job I was leaving him he still hasn't gotten one... I told him to give me and my family some space, but yet it's like he doesn't listen to me.. every time I tell him how I feel he promises to change what he is doing, but never does... advice would be greatly appreciated...