The problem is not with teenagers and their sex drive. It is with our culture, allowing promiscuity without repercussions, i.e. abortion, and if they DO get married, as soon as they hit a rough patch they get divorced.
Not only that, many marry while disregarding the commitment because it IS so easy to get divorced.
So, we have, "Oh, if I get pregnant I'll just have an abortion.", and "Oh, if I get married I can always get divorced."
It is a no win situation, unless we can push our morals back at least fifty years, which will never happen.
I certainly do not know what the answer is, but I teach my girls from a very young age that abortion is killing a baby, and that divorce is unacceptable unless their is some sort of abuse. Educating my own children is all I can do.
I just wanted to get that of my chest because many always talk about no sex before marriage but they never mention what age marriage should begin! The more marriage is delayed amongst our children the less chances they will be able to keep chase.
But in our day and age when we are seeing youth not only finish college but then go on to a masters degree and so on and delay marriage it will be harder and harder for marriage to be a choice for the young - as you say they will ditch marriage at the first rough patch.