I remember a quote made by George Bernard Shaw that said that both uncontrolled sexual promiscuity and the excessive enforcement of chastity can be considered vices. I agree with this viewpoint. We must strike a balance between the two, and such balances are inevitably different for all people.
As for me, Stoicism dictates that for a choice to be considered a vice, its consequences must do more harm to the person than good. In my case, a pre-marital sexual relationship would do more harm to me than good, as I am financially incapable at this time to support a potential child, a very possible consequence of coitus, and its mother. In someone else's case, pre-marital sex could be more beneficial than harmful, if he or she is more prepared to face the consequences that could result from it. Sadly, I myself have seen in my examples of pre-marital sexual affairs that have done more harm to the individuals than good, and such examples I feel are becoming more and more the norm these days. Religions in general tend to have such strict rules regarding sexuality because they fear the excessive harm these relationships can cause, but that does not mean that all pre-marital sexual relationships are harmful, so long as the participating parties are made aware of the consequences. I also feel that some religions shouldn't go full-bore on condemning sexuality as evil and forbid its members from participating in it. An example of this is the enforcement of celibacy in the Catholic clergy. If they were allowed to have families and utilize their nature-given power to procreate, many of the sex scandals plaguing the Vatican would be avoided. Sex holds within it the power to create human life, a power nature has given us. It must never be suppressed, but it must at the same time be respected and used with the proper timing, such timing being different for every individual.
