He liked me but did something with my best friend?

this guy i use to like called me everyday and we talked for hours and every 5 seconds he would tell me that he rly liked me and wanted to see me and stuff like that (keep in mind hes a major player) well one nite after we got off the phone he ended up going to my bffs house and they screwed and she knew i liked him and then nobody told me abt it for like a week and he still called me everyday and told me the same stuff and then wheni found out of course i was pissed and he still called me and told me how sry he was and stuff. but he hasnt talked to my friend since they did it and he still calls/txts/and ims me and tells me he wants to see me and he wants to come to my house..but he knows that i'm straight edge and i'm waiting until marriage!! so why is he doing this?? and what should i do?? sry so long :]