Everyone is entitled to their own standards. If that is yours, than you are going to have a hard time with any girl with male friends. Given enough time, it is almost inevitable that one person of a mixed sex friendship will proposition the other. These people obviously enjoy each other's company, else they wouldn't be friends. From there it is just a short skip and a hop to that inquiry. Not to pick on you, but that standard does come across as a bit insecure (kind of like those people who will only date virgins), unless she is a total slut who can't say no. In which case you better slap a chastity belt on her