Cherry something is not right here... you say that lately he has started kissing your neck... hello - but how does he get that close to kiss you on your neck?? its not an easy thing to do so he has to be pretty close and comfortable to be able to do that and what about you ?? you just stand there quietly while he does it. i know one thing, if any guy came that close to me I would certainly notice and move away...
So I tend to think there is more to the story.. maybe you were nice and cosy with the guy and now that he wants more you are panicking... and to tell him you have a BF well thats just real clever...

SOrry I dont buy your story - there is something else you are not telling us....