The obvious reason for declining marriage rates is the general erosion of traditional social conventions. A less obvious reason is that the median age for both sexes when they first wed is now six years older than it was for their counterparts in the 1960s. In 2000, Jeffrey Arnett, a developmental psychologist at Clark University, coined the term emerging adulthood to describe the long phase of experimentation that precedes settling down. Dating used to be a time-limited means to an end; today, it’s often an end in itself.

Yet the round-robin of sex and intermittent attachment doesn’t look like much fun. If you’re one of the many who have used an online dating service (among those “single and looking,” more than a third have), you know how quickly dating devolves into work. Tinder’s creators modeled their app on playing cards so it would seem more like a game than services like OkCupid, which put more emphasis on creating a detailed profile. But vetting and being vetted by so many strangers still takes time and concerted attention. Like any other freelance operator, you have to develop and protect your brand. At its worst, as Moira Weigel observes in her recent book, Labor of Love: The Invention of Dating, dating is like a “precarious form of contemporary labor: an unpaid internship. You cannot be sure where things are heading, but you try to gain experience. If you look sharp, you might get a free lunch.” In Future Sex, another new examination of contemporary sexual mores, Emily Witt is even more plaintive. “I had not sought so much choice for myself,” she writes, “and when I found myself with total sexual freedom, I was unhappy.”

We are in the early stages of a dating revolution. The sheer quantity of relationships available through the internet is transforming the quality of those relationships. Though it is probably too soon to say exactly how, Witt and Weigel offer a useful perspective. They’re not old fogies of the sort who always sound the alarm whenever styles of courtship change. Nor are they part of the rising generation of gender-fluid individuals for whom the ever-lengthening list of sexual identities and affinities spells liberation from the heteronormative assumptions of parents and peers. The two authors are (or in Weigel’s case, was, when she wrote her book) single, straight women in their early 30s. Theirs is the “last generation,” Witt writes, “that lived some part of life without the Internet, who were trying to adjust our reality to our technology.”

Weigel, a Ph.D. candidate in comparative literature at Yale, embarked on her charmingly digressive, nonacademic history of American dating after being strung along by a caddish boyfriend torn between her and an ex-girlfriend. His confidence that he was entitled to what he desired (even if what he desired was to be indecisive), compared with her inability to assert her own needs, dismayed her. How retrograde! The sexual revolution had failed her. “It did not change gender roles and romantic relationships as dramatically as they would need to be changed in order to make everyone as free as the idealists promised,” she writes. To understand how she, and women like her, came to feel so dispossessed, she decided to investigate the heritage encoded in the rituals of dating.