Why are engagement rings not given to men? Because not so long ago, presenting an engagement ring to a woman was not only a promise to marry–it was insurance.
In those times, for a woman to be part of the market of marry-able women, she almost had to be a virgin. A woman’s virginity was a prized state that once lost could not be recovered.
For men, the marriage market was not so harsh with regards to male virginity. Indeed, some quietly argued the opposite: Since the man was expected to take the lead in those sorts of things, the man’s experience in the newlyweds’ bedroom prevented an embarrassing, bumbling mess–or so went the justification.
Yet 50% of engaged couples became intimate before the marriage ceremony (and the other half were mostly liars). If the couple actually went through with the marriage, such a misstep could generally be ignored or forgiven. However, if the engagement was broken, it would be very difficult for the non-virgin woman to enter another engagement. She was now damaged goods in the marriage market.
So the value of the engagement ring became a kind of insurance policy against a broken engagement. If an engagement was broken, the engagement ring was kept by the woman, and its value served as compensation for the women’s lost virginity and reduced value in the marriage market.