Dating and purity
Even when you've been dating someone for a year, the lack of permanence that characterizes your relationship seems to add a certain frisson to everything you do with that person, from going on a Saturday hike to smooching on the sofa. It becomes a ritual in itself; it becomes a routine.Everything in your relationship gets some of its charge from the uncertainty, the unknown. Married sex is exciting, but its excitements are very different, and much more tender, than the instability of the hook-up scene.
Married sex does not derive its thrill from the possibility of the unknown. It is based on mutual desire, and it dispenses with the ordinary rhythms of marital sex, trading them for a seemingly thrilling, but ultimately false, story.
If you want to make sure of keeping it intact, you must give your heart to no one, not even to an animal.
Wrap it carefully round with hobbies and little luxuries; avoid all entanglements; lock it up safe in the casket or coffin of your selfishness.
By chastity, I mean conforming your body and your sexual self to God's vision of human sexuality as laid out in Scripture and articulated by church tradition — for married people, fidelity, and for unmarried people, abstinence. Simple: It's difficult; and now, even more so than when Lewis wrote, we live in a society that does not give us much support for living chastely.
Indeed, American culture seems determined to mock and ridicule chastity as much as possible.