Why do some women get guys to be their boyfriends, while others only get them to be -calls?

I think you are making a mistake alot of women make, confusing a man's natural urges with a call. Men stay with women because they get alot from being with them (and yes, alot of it is ). You need to accept the fact that all guys will want to sleep with you and that alone does not mean they are bad or won't have a relationship with you.