Purity peddlers construct a false universe where there are pure virgins who wait until marriage, and then there are slutty whores who are going home with different men every night of the week. The truth is that most adults will have a great many important relationships in their lives – some of those relationships will be romantic, and some of those will be sexual. That's a good thing: our relationships with other people, sexual or not, are how we grow, evolve and learn about ourselves. They're how we figure out what love is, what we like physically and emotionally, and how to negotiate our own needs with someone else's. Despite the claims of the wait-till-marriage camp, waiting to have sex won't protect you from heartache, frustration or love lost. But a variety of fulfilling relationships, sexual and not, will make you a more well-rounded, compassionate and self-assured person.
My point isn't that everyone should have sex before marriage – people should determine for themselves when they are ready to have sex. For the vast majority of people, that's going to be before they're married. Making that choice isn't a moral failing. On the contrary, it's often a great, healthy, overwhelmingly positive choice. Whenever you choose to have sex, the cultural message that waiting until marriage is the best choice is simply wrong. And it's wrong for almost everyone.