So sick of losers,never had a bf and im 21?

i am a good girl,i care and im someone that people can trust. i am 21 years old and havnt even hd 1 boyfriend,just users,liers trying to get in my pants,and played.i get compliments all of the time on my looks ,im not ugly but why am i always the one guys wanna just leep with?it hurts because thats the only thing they want from me.and no i dont give it up lke that,i handle myself with cl.i never meet guys in person.so i joined a few dating sites,i met guys there but they just want ...i cant win!i even tried not thinkin about it,but its hrd becase im always alone,my friends are in school so i dont talk to them as much..why does this always happen?am i doing something wrong?and yes i kow that im still young..