As millions of Americans are rediscovering, monogamy isn't easy. Sweeping changes in American sexual behavior have plunged many "liberated" men and women back into the kinds of relationships their parents, or possibly their grandparents, had, and which only a decade ago were widely assumed to be dead as the dodo.

The fear of AIDS has suddenly changed that. A monogamous relationship -- one based on fidelity and trust between partners -- is now the only safe relationship. The suspicion that our partner may be playing around is no longer just a question of throwing a tantrum, breaking the dishes, going home to mother or writing him/her off as one of life's bad choices -- it can be a death sentence.

Under these circumstances, monogamy seems like the best idea -- surely better than celibacy, which has always been notoriously difficult, even for saints, and which also isn't much fun.

However, sex alone, powerful bond as it is, has never been expected to keep a couple together over the long haul. We usually discover everything there is to know about a person sexually rather rapidly. It is, after all, possible to have a wonderful sexual relationship with someone without really knowing very much about him/her at all. While many of the problems of living together in a long-term monogamous relationship can be solved by good sex, not all of them can be resolved in bed. Indeed, the ancient notion of the honeymoon was intended to let the couple get all of that out of their systems before settling down to the task of making a life together.

What truly binds people together on a permanent basis is romance, curiosity, shared interests, affection, caring about each other.

You will notice that I have put "romance" first. There's a good reason for that. Romance remains the most powerful bond between people. If there's a strong romantic bond plus sex, everything else in the relationship can be negotiated. People stay together because each makes the other feel special, and stay together over the long haul because they never stop trying to make the other feel special. And feeling special is what romance is about.

Women have usually understood romance better than men, I think, at least in the past couple of centuries. There's an ingrained belief in America that the whole subject makes real men uncomfortable. Women, on the other hand, even in the middle of the sexual revolution -- when they were, at least statistically, breaking every rule that hitherto governed their behavior -- have been buying romantic fiction in ever-increasing numbers. Real-life romance, however, has nothing to do with Barbara Cartland's fantasies. It's an attitude toward one person, the fact that he or she makes you feel good about yourself, helps to bring out the best in you, understands more about you than anyone else, but still doesn't understand everything.

Curiosity, the feeling that there's still something about the person you love that you don't understand -- a few surprises left, some inner core you haven't yet touched -- is another strong reason why people stay together. Think about it. Why do women wear "romantic" lingerie to please men who may well have seen them naked a thousand times? It is because the age-old idea of pretending to hide a woman's charms so that the man can imagine them is a powerful sexual stimulus. It may explain why women will sometimes stand in the bathroom naked, brushing their teeth in full view of their partner, then put on a nightgown before turning out the lights and going to bed.

Our lives are so busy that it's hard today for people to devote much time to making each other feel special. Between the scramble to earn more, become successful and save up for the future, there may be time for sex, but there's never enough time for making each other feel good in any other area.

And yet, that's what monogamy is about. We have to learn to make time, to slow down the clock. We have to invest something in simply learning to enjoy each other in small, everyday ways. My grandfather and grandmother were married for at least 50 years; every day he brought my grandmother her breakfast on a tray. Admittedly, it was prepared in the kitchen by a maid, but still he insisted on taking it up to her, and sat for a few minutes while she drank her tea, before he went to work. She shopped every day for the flower he invariably wore in his buttonhole, and there was clearly some complicated and secret code between them that had to do with the color and species of the flower, a kind of secret language that made them smile and was never explained.

I remember that when they were in their eighties, I asked my grandfather what my grandmother would think about something I was planning to do, and he gave me a smile, as if it were the funniest question in the world. "Oh, I wouldn't know that," he said, chuckling. "She never ceases to surprise me, your grandmother does." He seemed to look forward to finding out himself what Grandmother's reaction would be, and it occurred to me, even then (I was in my early twenties), that one of the reasons these two had stayed together happily for so long was precisely that they didn't know everything about each other. There was still, after all those years, something to wonder about, an element of mystery -- and that, in its own way,Men need to relearn what their fathers and grandfathers knew, if the new monogamy is going to work. was far more romantic than his bringing her breakfast in bed, or her choosing his daily flower for his buttonhole.

The French have a saying, "Tout comprendre, c'est tout pardonner" (To understand everything is to forgive everything). While I've never been convinced this is true, I think it is true that you should never know, or think you know, everything about the person you're living with. Trusting is one thing, that's essential, but there should always be something new to discover, or you've got real trouble. Indeed, one of the charms of monogamy over quick affairs lies precisely in the continuous process of discovery and change. It is only by living with someone for a long time, and sharing the various crises of their life, that we discover their strengths, their hidden courage, their weaknesses -- the real person, as opposed to the surface.

Admittedly, not all of these are pleasant discoveries, but that is simply part of the undeniable fact that all life is a gamble, with no sure things. A short affair with someone can be exciting, but it's only in long-term monogamy that we're going to discover whether he or she is supportive when we're ill, caring when we're in trouble, generous when generosity matters, tough-minded in a crisis, understanding of our needs ... These are things that can only be revealed gradually, which is one of the reasons why any successful monogamous relationship requires a considerable degree of patience.

Patience and caring may not sound romantic, but that is what romance comes down to, rather than flowers, candlelight and remembering birthdays -- though these too are small signs that we care, and therefore not trivial. Men need to relearn what their fathers and grandfathers knew, if the new monogamy is going to work -- all the more so since sex is no longer the big mystery it used to be.

A good sexual relationship is assumed in a long-term relationship today; indeed, most relationships begin with that. In the generations that preceded ours, satisfactory sexual relationships, while by no means uncommon, took a long time to achieve. Women were for the most part innocent; men were uneducated in women's needs; pregnancy was unavoidable and the whole subject was taboo. But it was at least partially this long process of mutual education in pleasure that helped give Victorian marriages their awesome stability. Much time had to be spent learning what every teen-ager knows, or thinks he or she knows, today.

We, on the contrary, start with all that, but the result is that we must find more to put into a monogamous relationship than our grandparents did, and have to work harder at it. They had the mysteries of sex and the inevitability of large numbers of children to hold them together. We cannot expect competitive careers, or saving up for a condo and a BMW, or shared exercise or gourmet cooking to substitute for the big-league concerns and passions that used to keep people together from early marriage to death -- and to keep them interested in each other all the while.

What we have to find are those things that make living together not just a refuge from the dangers of the single life, but the central life experience that puts everything else in context. We have to reinvent romance, not in the old sense of sexual longing, which in most modern relationships make no sense (the unattainable having already been attained), but in the sense of deep caring about the other person, making ourselves interesting to him or her, believing always that in the end nothing is more romantic than two people choosing, voluntarily, to spend their lives together.

Living monogamously because it's safer isn't enough to hold two people together. The truth is that living monogamously is the most daring and romantic of adventures, the only way to truly know another person -- and ourselves.

Michael Korda is editor in chief of Simon & Schuster. This article first appeared in Self magazine.