Even in the ‘good old days’ when people were strictly forbidden any kind of pre-marital sex, when kisses were scandalous, etc, etc, it was assumed that young men’s passions were fleeting while young women would try to string along several suitors, a variety of status as much as anything else.
Shakespeare’s Romeo mopes and pines for Rosaline until he meets Juliet and then so much for Rosaline:
I have forgot that name, and that name’s woe.
Wisdom suggests that the young will be (relatively) frivolous and will make all the same old mistakes that their elders have long tired of making. This idea is the source of much literature, jokes, pop songs etc.
Accepting frivolousness – sexual or otherwise – in a world-weary way, making it the subject of humor, etc. doubtless produces cultural feedback that encourages young people to do just that.
But short if issuing hairshirts to co-eds I have no idea what we could do about it now.