“THIS IS SO exciting!” trills a young woman, squeezing her friend’s arm. Laid out before her, in the Olympia exhibition centre in west London, is the National Wedding Show. Some 300 merchants have turned up to sell everything that is needed to throw a wedding, and a great many things besides. There are florists, harpists, teeth-whiteners, tiara-sellers, a fireworks firm and more than a dozen photographers. A new company, Hitch and Pooch, arranges for people’s dogs to play a role in their weddings—as ring-bearers, say. Every two hours a blast of music announces a catwalk show consisting entirely of wedding dresses and grooms’ suits.

Marriage is often said to be ailing. It is “fashionably dismissed” and “taken for granted”, sniffed Iain Duncan Smith a few years ago when he was Britain’s secretary of state for work and pensions. Social conservatives argue that a once-great institution has been undermined by ever more blasé attitudes to premarital sex, cohabitation and divorce—and, in the past few years, by the legalisation of gay marriage. Successive American presidents have poured money into programmes that aim to promote marriage among poor people.

In some ways the worriers are right. For hundreds of years marriage was an essential step on the road to full adulthood in Western countries. In pre-industrial England all single women, no matter how old, were “maids”, and all single men were “lads”. Preachers argued that marriage was the crucial bond holding together the household, which was, in turn, the foundation of society.

By the mid-20th century marriage was almost unavoidable. The idea that people ought to wed and then form a household with a primary male breadwinner was, in the words of Stephanie Coontz, an American historian, “like a steamroller that crushed every alternative view”. People tied the knot at ever younger ages: in the 1950s and 1960s the average American bride was too young to consume alcohol at her own wedding. Europe was almost as marriage-mad. As late as 1972 fully 87% of French women aged between 30 and 34 were married. These days just 43% of French women in their early 30s are married. That is part of a broad retreat. In Argentina weddings have become so rare that one outfit, Falsa Boda, has started staging wedding-themed parties, complete with fake vows. And in many countries marriage has become unmoored from parenthood. In 2015 two-fifths of all American babies were born to unwed mothers. In France the proportion is 59%; in Colombia it is 84%. Just 21% of Britons aged between 15 and 24 now agree that people who want children should get married, half the share in 1989. The West seems set on a different course from the rest of the world, especially Asia, where traditional attitudes persist. In rural China a single man in his late 20s is seen as pathetic and perhaps even dangerous. In Japan only 2% of births are to unmarried women; in India and across much of north Africa and the Middle East the share may be even lower. In many poor and middle-income countries the law still does not recognise unmarried couples and treats their offspring as virtual non-people. This special report will argue that much of what people think they know about marriage is wrong. In the West the institution is more resilient than it seems, although profoundly changed since the mid-20th century. In Asia, it is much more fluid and unstable than it might appear. What look like fundamental cultural differences between West and East are often just differences of timing and degree. Marriage is being transformed almost everywhere, and in many of the same ways. But different countries are at different stages of the journey.

From west London to Chinese villages to Indian slums, three great changes are afoot. The first is that marriage decisions are being wrenched out of the hands of parents and relatives and made by the young people themselves. The clearest sign of this is the almost universal rise in the average age of marriage (see chart below). There is still a large gap between Norway, where women marry at an average age of 32, and Bangladesh, where they wed at 19. But there is also a crucial difference between marrying at 19 and at 16, which was the average in Bangladesh in 1974.

The second change is the emphasis on conjugal love. For much of Western history romantic love, or “familiarity”, was held not only to be unnecessary for a strong marriage but antithetical to it. William Gouge, an influential Puritan writer in 17th-century England, lambasted women who called their husbands “sweet, sweeting, heart, sweet-heart, love, joy, dear…duck, chick, pigsnie &c”, terms that struck him as undermining the wifely deference essential for a successful union. Many English couples probably ignored Gouge and went on murmuring sweet nothings, which is why he was able to collect so many of them. But his view was perfectly orthodox at the time.

Today love is triumphant. The merchants at the National Wedding Show invariably report that every couple insists on their wedding being romantic and special. “You don’t have to get married these days,” explains Anna Muckart, who makes charming wedding invitations. And because weddings are no longer obligatory, they must be extraordinary. Marriage has changed from being a rite of passage to a celebration of love and commitment—a sign that two people who already live together are ready to commit themselves further. Asian brides and grooms often demur, arguing that marriage should be entered with a cool head and that weddings join families, not just couples. But even they now stress what they call “compatibility”.

When love is the basis for marriage, it follows that a marriage without love should be put asunder. The third great global change is the growing acceptance of divorce. It is now more common in many countries, especially fast-modernising ones where women are becoming economically self-sufficient. These days China and South Korea have divorce rates above the European and OECD averages.

Where breaking up is hard to do

Churches and governments have often tried to resist these changes. Usually they have been humiliated. In America, even government-funded studies conclude that federal programmes aimed at strengthening marriage have almost no effect. Attempting to preserve unions by making divorce more difficult might just lead to fewer marriages. In Chile divorce was almost impossible until 2004 and is still not easy. Probably not coincidentally, Chile has the highest proportion of births outside marriage among the 35 members of the OECD.

Almost everywhere marriage is becoming less obligatory, less coercive and less dutiful. It has not, however, lost any of its appeal or its private binding power. A recent survey of young Britons found that 93% aspire to marry. Even in countries where divorce is socially acceptable, people still believe that marriage is a special bond, not to be made or broken lightly. Its effects are expressed more accurately by novelists than by statisticians. The single life is rather like riding a moped, explains a character in “The Age of Grief”, a story by the American writer Jane Smiley: you feel every bump in the road. A marriage, particularly a marriage with children, is like an 18-wheel lorry barrelling along.

Study after study testifies that married people are healthier, wealthier and happier than unmarried ones, and less likely to split from their partners. It is hard to tell how much of this is because they are married and how much is a selection effect — happy, healthy people in strong relationships being more likely to get married in the first place. But academics who have tried to control for those things still tend to find a marriage effect. Wedlock seems to increase human happiness even allowing for the fact that many marriages fall apart.

In rich countries, the institution of marriage increasingly confers advantages on people who already have many. Affluent, highly educated men and women marry late and after careful consideration. Their marriages are highly successful—on average, almost certainly the happiest and most fulfilling that the world has ever seen. Among this privileged group, divorce is increasingly rare. The marrying classes of the West are building unions as resilient as the dutiful ones found in poorer countries.

For many others, however, marriage seems to be moving out of reach. The working classes have become much less likely to marry than the middle classes, and when they do, their unions are more liable to break down quickly. Most working-class people still idealise marriage, but think of it as something to be undertaken at some point in the future, or perhaps not at all.

This report will examine the growing social divide in Western marriage, as well as an even more extreme social cleft in China, where a shortage of women may leave tens of millions of poor men without brides. But it begins in India, where weddings rival cricket as the nation’s favourite pastime, and where old marriage practices are being discarded at alarming speed.