Pre-Marital Sex

This is less relevant to Buddhism than I would have liked but I was thinking about the whole abstaining from sex until marriage thing. The opinion that everyone should abstain from sex until they are married is still around; many Christians still think that this is relevant advice for our contemporary society. I was thinking about it and decided that society has changed heavily since the onset of that guideline. That guideline/rule was put into place many years ago (around 2000 at the least); at that time the life expectancy was much less for any given individual. As such, when people were biologically  ready to produce children, they got married. They, on whole, seldom had to repress their sexuality. In this society, people live to be much older and, as such, tend to get married later in life. These individuals who choose to abstain from sex, assuming that they actually have an inclination towards sex, are only bottling up their sexual energy. I think that  this may not be the best idea, and probably isn't precisely what the Christian God would want. He may want people to have sex only after they are married, but his rules would have to be altered slightly to apply today.