A friend emailed me over the holidays, "Eliot Spitzer and his wife have called it quits. What does this mean?"
In any marital breakup, there are at least two significant parties -- and possibly more. But when one of them is a former New York governor, there is always a third party: the public.
One might have thought that interest in the Spitzers' marriage would have died by now. He resigned as governor in 2006 amid a prostitution scandal. So much time has passed. Why do we still care?
One could ask the same question, of course, about so many prominent political marriages that have imploded over infidelity. Jenny and Mark Sanford -- he the former South Carolina governor and now a congressman newly married to his paramour. Dina Matos and Jim McGreevey, the former governor of New Jersey. Marianne and Newt Gingrich. Donna Hanover and Rudy Giuliani.
For that matter, why do we care, 30 years on, that Joan Kennedy hauled herself out of rehab and depression -- post Chappaquiddick -- to campaign alongside her husband, Sen. Ted Kennedy, to boost his presidential chances? Or that Hillary Clinton stays married to Bill after his philandering? If I may paraphrase her attitude about the question, she believes it's a private decision.
And yet we obsess as though it's our business, too.
"Domesticated," about a political couple's life post-sex scandal, opened on Broadway this fall. The CBS series "The Good Wife," which the writers say was inspired by Silda Wall Spitzer, tells the story of a district attorney who goes to jail on corruption charges after a relationship with a prostitute -- but then rebounds to win the governor's race. The original Netflix series "House of Cards" portrays a vengeful congressman who begins sleeping with a news reporter, with his wife's consent. The wife, who is having her own side fling, only wants to be sure that she and her husband are getting more out of his affair than the reporter is.
One reason for the public obsession may be that we are deeply ambivalent about infidelity in our own lives. Marriage therapists estimate as many as 80 percent of marriages survive infidelity.
Of course, reliable statistics are scarce, largely because people don't want to own up to their affairs. However, the explosion in couples counseling serves as one proxy for the troubles in modern marriages.
In 1996, there were about 1,800 couples counselors nationally, according to the Department of Health and Human Services. By 2012, the government's Bureau of Labor Statistics was listing "marriage and family therapist" as one of the top 10 growth fields, expected to expand 41 percent by 2020.
Membership in the Beyond Affairs Network is another proxy. An international support group for people who have been betrayed by an intimate partner, BAN in 2006 consisted of 61 groups in 27 states and 10 countries. By 2013, it had mushroomed to 129 groups in 38 states and 16 countries.
The Internet and social media, with all of their benefits, have also unfortunately been a great boon for affairs. Sex and marriage researchers Katherine M. Hertlein and Fred P. Piercy noted in 2008 that "the prevalence of this problem for couples is increasingly rapidly." Experts say the Internet has three characteristics that suit it for this role: the "Triple A" of accessibility, affordability and anonymity.
We claim that we care about Eliot Spitzer's romantic fidelity because it says something larger about his ability to serve the public ethically. But the source of our fascination is likely much closer to home: We see ourselves in the mirror of the decisions our most prominent couples make.
Anne Michaud, interactive editor for Newsday Opinion, is a member of the Newsday editorial board; email@example.com.