Like everything else, relationships change over time. There’s a formula to them that is remarkably consistent.

Relationships start out full of passion and excitement. The object of our infatuation is a paragon of virtue or beauty or intellect (maybe all three!).

We can’t spend enough time together. Love blinds and blinkers us. Love, as Shakespeare put it, is “dearer than eyesight, space and liberty.”

This is the “pedestal stage,” you might say, and it’s highly unrealistic. No one can live up to the demands and expectations of “pedestal hood,” because no one exists inert and idealized like a statue. We’re all flesh-and-blood flawed. And when after some time in the newly developing relationship these flaws are revealed, as they always are, it can come as a shock. What—you’re not perfect? But of course: no one is.

Some relationships don’t survive the shock. And that’s too bad, because it’s based on the faulty premise of perfection. As they say, the perfect is the enemy of the good. And people generally get that.

If so, the relationship can move on to a second phase, characterized by the messy dimensions and exigencies of real life.

Couples date, fall in love, get engaged, get married, have careers, have kids, deal with aging parents and financial problems and the stress of work. Life is a hurly-burly of constant distraction and harried dissatisfaction. Sometimes partners are so busy they hardly see each other.

Almost half of all marriages don’t survive this stage.

Then things change again. Kids leave the nest. Aging parents move away or die. Careers peak and then end.

Now two people have the time and opportunity to contemplate life alone together. It can be scary, because it’s been so long since they’ve had the experience, and hard, because by this time their lives have been beset by losses: the loss of their earlier passion, energy and enthusiasm; the departure of kids and loss of parents; the end of jobs; a sense of marginalization in a society that worships youth.

So then what?

Then is the time for the couple to take stock, to discover a deeper and perhaps more meaningful intimacy, to let down their emotional guard and express vulnerability and tenderness, to revisit old and find new interests in common, to forge once again the emotional bonds that drew them together in the first place.

There’s an urgency to this mandate, because mortality looms. A good question to ask is: “Since today could be our last day together, how are we going to spend it?”

These are the long and strong chords of a lifetime relationship. And with time, effort and affection, with humor and honesty and understanding—and most important of all—appreciation for the miracle of still being together, the final stage can be the most rewarding of all.

Les is a longtime Evanstonian and RoundTable writer and editor. He won a Chicago Newspaper Guild best feature story award in 1975 for a story on elderly suicide and most recently four consecutive Northern...