I’m the skeptical, jaded type who believes the passionate kiss former Vice President Al Gore and his wife Tipper exchanged in front of the Democratic National Convention in July of 2004 was most likely staged. But I am truly puzzled, with the rest of America, on why a couple who seemed so together is now splitting after 40 years.

I’m not only puzzled, but also disheartened. Because I respect and admire couples who have made it beyond their silver anniversary. Like everyone else confused by the Gores decision, I suppose I attach a layer of immunity to the partners who’ve raised their kids, launching them successfully. Now they are safe to buy that double burial lot because, like or not, they are sticking together.

No so, says Betsey Stevenson, an economist at the University of Pennsylvania’s Wharton School who studies family trends. In a recent interview for the Associated Press, Stevenson explained that marriages are more likely to fail in the first 10 years, but after those years the divorce rate pretty much stays the same. So a couple who celebrates 50 years is just as at risk as, say, Eric and I who have been together 14.

“We’ve simply grown apart” is the reason the Gores give.

And, even if something else did happen that the media hasn’t yet uncovered, that reason is one of the most common listed by divorcing couples among some others: money, infidelity, poor communication, change in priorities, lack of commitment to the marriage, addictions, and physical, emotional, or sexual abuse.

Let’s face it, even with two well-adjusted adults who care about each other, marriage involves a ton of hard work, sacrifice, generosity, selflessness, and other virtues that don’t come naturally to most of us. If we don’t diligently work on our relationship, it will decay. Quickly.

In fact, the longitudinal study published in the September 1999 issue of The Journal of Developmental Psychology, called “The Nature and Predictors of the Trajectory of Change in Marital Quality for Husbands and Wives over the First 10 Years of Marriage,” charts the decline in the quality of marriages of more than 500 copies surveyed over 10 years. According to the study, the first four years involves the steepest decline in marriage satisfaction and then a second decline happens at years 8, 9, and 10, the phenomenon that we know as “the seven year itch.”

Natalie Low, Ph.D., a clinical psychologist and instructor at Harvard commented on the study in Amy Dickinson’s Time piece, “From ‘I do’ to the Seven-Year Itch,” and provides the best marital advice of all, I think. She argues that our expectations are too high. We buy into illusions and dangerous messages sold to us constantly on the airwaves, internet, billboards, television networks and at the movies. We expect our marriage to have the romance of Julia Roberts and Richard Gere in “Pretty Woman” all the time. We expect our jobs to be fulfilling all the time, and for our children to be honor roll students with a sports scholarship. Low says that if we can successfully temper our expectations, we’ll be more satisfied with what we do have.

“The facts of life are very grinding,” Low says in the Time piece, “so the reality of marriage is grinding. There is no obvious course to follow, so couples just have to keep working. A person sees dramatic changes during a marriage, so a couple has to be committed to a way of life.”