If your mate was deceiving you (or you had been unfaithful to him), who could you count on to keep your secrets? For many women, the Internet is a safe haven, full of strangers you can confide in. Is this what passes for trust in the digital age?
My husband and I haven't been getting along so well lately....

This is the public face of marital discord. It's the kind of secret we entrust to friends with a rueful smile, a roll of the eyes, perhaps a hint of resignation. He's driving me crazy, but what can you do? It's perfectly acceptable—funny, even. After all, haven't we all been there?

And then there's the kind of marital secret we don't dare tell our friends because it's too potent, too painful, too threatening. It involves a betrayal of the most intimate of human relationships, of the trust that is the very bedrock of most coupled people's lives. He's busy watching porn while he's supposed to be watching the baby. Or, he's so boring in bed I have to fake it with him. Or, I've attached a GPS to the underside of his car to see where he's going. Or, I never thought I'd be the one having an affair.

These days, more and more Americans seem to have the latter kind of secret, at least if you believe last year's headline-making study that cheating is on the rise in some age groups. The research was based on data from 1991 to 2006 from the General Social Survey (the National Science Foundation's biennial snapshot of the behaviors and opinions of American adults): Although lifetime infidelity rates hover around 25 percent for men and 15 percent for women, rates for women under 35 are on the rise, and men over 69 are straying more than ever before. The number of unfaithful wives under 30 increased by 20 percent; husbands, by 45 percent.

We can probably thank Viagra for the surge in extracurricular activity among older men; as for the younger women, experts point to a loosening of cultural mores and to women's increasing economic independence—the assumption being that an economically dependent woman is more likely to think she can't afford the risk.

And then there's access. Digital technology is the most interesting thing that's happened to infidelity since key parties. By now we all know that thanks to e-mail, texting, cell phones, and the Internet, stepping out on your significant other has never been easier. You can find websites like AshleyMadison.com, which caters to married people who want to have affairs, and Casual Encounters on Craigslist, which caters to anyone who wants to do practically anything. We know, too, that it's never been more perilous, because every technological innovation that enables the cheater also makes it that much easier to be caught. But what gets lost in the juicy drama of high-tech hookups and cybersleuthing is how technology makes it possible for people dealing with infidelity simply to talk to one another.