It's not really news to anybody that premarital sex has become the overwhelmingly accepted social norm since before the Beatles broke up. And even if people don't always go at it by the third date any more, you can basically assume that any serious young couple will at some point throw some Marvin Gaye on the hi-fi and coat each other with pancake syrup. This is probably as it should be. We have the technology to keep the viruses and fetuses at bay. We're getting married at a more advanced age.
Sex is cheaper than going to the movies.
And guiltless sex is basically why we're in our twenties for 10 years anyway. But we've forgotten something. Essentially, no technology or social progression really has the power to alter ethics. So some people are still holding out. Some people really want their wedding night to be their big moment of truth.