STALKER??!! I need some help with how to handle this problem...?

I've known this boy since I was about 7. We went to primary together, and really didn't get along. Around month ago, he started to speak to me on Facebook. He told me how he secretly liked me when we were in primary. I have a boyfriend, and he knows that. But he keeps asking if he can come round to my house- One time he asked at half past midnight to come round! I'm starting to get a little freaked out. He's actually quite nice- so I don't want to tell him to go away. I've even disabled my facebook account for 2 weeks, and after that he still talked to me. He knows where I live, even though I've never told him in my life. It really started to worry me when my bestfriend tol me that he may be a stalker (I know it sounds silly). I'm getting really scared now because he is a few years older than me- and really thinks he has a chance with me even though I'm not single.. HELP!?