My guy and I head up the Couples Ministry at our church. We get to spend time with couples who are getting married, doing the premarital counseling for the pastor, and with other couples who may be struggling to find happiness and fulfillment together. This is a newer ministry at our church, and it’s been very rewarding for us; causing us to grow closer and really think about what is important in a thriving marriage, and what isn’t. We also have three teenagers living in our home, which means a lot of friends, hormones and borderline inappropriate silliness. On a given day, we can leave our loud, chaotic house to meet a couple in crisis at a dark, quiet coffee shop for an hour or two, only to return to more noise and friends, especially in the summer months. So we spend the majority of our time together with one of these two groups of people.
The irony is this: we constantly tell these hormone-infused, adult-bodied children to say no to sex, wait until you’re committed and then have a great sex life. The subject is raised so often, and when friends are over jokes are made, so we use any opportunity we can to share our thoughts on premarital sex. And we keep telling these overwhelmed, exhausted married couples to have sex more often, explaining the value of sharing this special gift with your beloved on a regular basis. What does this say about our society? Is it really all about sex? Or could it be more about stubbornness and rebellion?
I can’t tell you how many women I have talked to about having a promiscuous past while they were single, and a non-existent sex life in marriage. There is guilt for the past and resentment for the present. And it can be really hard to tell these teens to just hold on, wait for the best sex possible in marriage, when in reality, it may not be the case. It makes me wonder if it ever was about sex at all, or if it was more about getting around the rules?
What if we approached sex as a celebration of two committed lovers, instead of a divisive tool to display our independence and power? It can be, but so often is distorted. It would make for a easier talk with these rowdy teens, as well as the married couples we spend time with. This is a wonderful explanation of the plan for sex within marriage given by John Mark Comer: http://www.youtube.com/watch?v=bF_5wbmrEsc
howsyourlovelife 
The reason those girls with a promiscuous past are having non-existent sex lives now is precisely BECAUSE of their promiscuous past. Those who remain chaste/virgins until their wedding nights have far better, healthier, guilt-free, and frequent sex throughout their married lives. Might be something to pass on to your teenagers as some extra motivation to not have sex yet. And also, encouraging them to marry during very early adulthood rather than waiting until they gain life experience (which nearly always includes sexual experience, especially if they go to college).