I once heard a story as part of a sermon by SM Davis, I believe. I can't recall the exact way he told it, so this is my rendition of his basic story idea. I really like the idea behind it, although this is more focused on girls, no matter what your gender, your heart should be guarded. Never under estimate the value of your purity, both physical and emotional. Some times more emphasis is put on the aspect of physical purity, that we forget the tole emotions can play in the whole arena of love too...
Imagine: Sally, standing there with her big paper heart, perfect with smooth curvy edges. Such a Pretty Heart. Enter: Mr Tall Dark & Handsome. Sally is in love, and tears off a piece of the paper heart and gives it to Mr TDH. It was her first love, and he got a decent sized chunk of her pretty paper heart.
Eventually, the love dies, fades, wears off, fails to excite, and then there is another Mr. He is not quite as dashing, but much more interesting. Mr Interesting is given his share of her pretty paper heart, it still mostly has its pretty shape, there is only one raggedy edge. Of course, interesting fades into a little boring over time, but there was never a dull moment with Mr Adventure. Sally wanted to give him the best of her heart too, so she tore off a piece from the untouched side.
On and on she goes tearing pieces off her heart, and giving them away. Her once pretty little heart was now jagged and torn. It was rough. It was only a fraction of it's original size. It really wasn't very pretty any more, nor did it resemble a heart shape in almost any way.
After college, Sally met Mr Right, and everything was perfect. Almost. Here she stands with her jagged little heart. It's not pretty anymore, but it's all she has left to give. She stands at the altar and gives this man her whole heart. What she had left anyway. He deserved more. So did she.