Sex before marriage is like this:
Imagine you had your eye on an awesome new car. You are saving your money, dreaming of someday owning it, even though it might be a long way off, you are working for it. You have talked about that car, and talked about that car so that everyone who knows you, knows “that’s your car”. Then one day you stop by your rather wealthy and successful dad’s house and discover your dad has bought that very car! You can’t believe it! You think, “What? That’s MY car! HE BOUGHT MY CAR!!”, and you resent that now your dad is going to be tooling around in your dream ride. Over the course of the week, you stew over that, and the more you think about it, the more your anger, resentment, and sense of entitlement grows, until one day, you slip in Dads house and take the keys without permission, and take the car out for a spin. And you total the car.
Your Dad gets the call when you land in the Emergency Room, and he is distraught with concern over your welfare. Once he knows you are not seriously hurt, he is baffled to learn the car you were driving was the beautiful new car that he just purchased. When you confess your feeling of resentment over his purchasing for himself the car he knew was your dearest dream, you learn that he had bought it not for himself, but for you, and had intended to give it to you that weekend as a surprise.
Imagine how that would make you feel, to realize your misguided heart-attitude, that in essence, you had stolen what was intended to be a very special gift from a loving and generous father, not only depriving yourself in your covetousness, but ruining what was sure to have been one of your dad’s greatest moments as he anticipated the joy of bestowing his gift to you. In the end, something very valuable was lost, and more than one person got tragically and irrevocably cheated and robbed of something precious.