My son, at the age of 14, will already have heard 1 Corinthians 6:9-10 read and preached on at least 10 times in the church he attends every single Sunday, as well as have been instructed thoroughly in Christian morality in preparation for his Confirmation.
Besides this formal instruction, he will have grown up in a household where mom and dad honor their marriage commitments and hold them to be a sacred and essential part of his home life.
If I actually have to take him aside at the age of 14 and explain to him that adultery is wrong and that married women are off limits then I've wasted 14 years of his life up to that point.
I was a 14 year old boy once and I will not pretend for a second that if a teacher who looked like this offered to have sex with me that I wouldn't have been tempted. In fact, I think there is a very good chance that I would have done it. However, I would have also known it was wrong. It is unfortunate that many see this as some sort of "victimless" crime.