You shouldn't judge someone who is abstinent.
John has been dating Jane for a few months when she tells him that she won't have sex before marriage.
John wants to tell Jane how he feels about her admission.
John respects Jane's position on having a sexual relationship.
John calls Jane a tease and tries pressuring her to have sex with him.
John is free to decide if he wants to pursue a long term relationship with Jane.
John loses any chance he had of being with Jane again.