WITH his slick navy suit, silver watch and non-stop smoking, Yu Feng is an unlikely ambassador for Chinese family values. The office from which he operates, in Chongqing in western China, looks more like a sitting room, with grey sofas, cream curtains and large windows looking out on the city’s skyscrapers. Women visit him here and plead for help. They want him to persuade their husbands to dump their mistresses.

Mr Yu worked in family law and then marriage counselling before starting his business in 2007. He charges scorned wives 100,000-500,000 yuan ($15,000-75,000); cases usually take 7-8 months. He befriends both the two-timing husband and the mistress, encouraging them to find fault with each other, and gradually reveals that he has messed up his own life by being unfaithful. Most clients are in their 30s and early 40s. “This is the want, buy, get generation,” he says; sex is a part of China’s new materialism. But changing sexual mores and a rocketing divorce rate have prompted soul-searching about the decline of family ties. Mr Yu claims a 90% success rate.

The ernai, literally meaning “second wife”, is increasingly common. So many rich men indulge that Chinese media sometimes blame extramarital relationships for helping to inflate property prices: some city apartment complexes are notorious for housing clusters of mistresses, paid for by their lovers, who often provide a living allowance too.

It is not just businessmen who keep mistresses: President Xi Jinping’s anti-corruption campaign has revealed that many government officials do too. According to news reports Zhou Yongkang, the most senior person toppled by the current anti-graft crusade, had multiple paramours; former railways minister Liu Zhijun is rumoured to have kept 18.

China has a long history of adultery. In imperial times wealthy men kept multiple concubines as well as a wife; prostitution was mostly tolerated, both by the state and by wives (who had little choice). Married women, in contrast, were expected to be chaste. After 1950 concubines were outlawed and infidelity deemed a bourgeois vice. Even in the 1980s few people had sex with anyone other than their spouse or spouse-to-be.

Over the past 30 years, however, sexual mores have loosened and more young Chinese are having sex with more partners and at a younger age. Some clearly continue to wander after marriage. Some 20% of married men and women are unfaithful, according to a survey of 80,000 people in 2015 by researchers at Peking University.

In many respects growing infidelity is a predictable consequence of economic development. People are increasingly willing to put their own desires above familial obligations or reputation. Improved education and living standards mean they have more financial freedom to do so. Most Chinese couples previously had few chances to meet members of the opposite sex in social situations after marriage, but migration means that many couples live apart. Even if they live together, the pool of temptation has grown larger and easier to dip into, thanks partly to social media.

Businesses like Mr Yu’s indicate that not all spouses see affairs as an unpardonable offence. But surveys also suggest that infidelity is the “number one marriage killer”. Last year 3.8m couples split, more than double the number a decade earlier. China’s annual divorce rate is 2.8 per 1,000 people (also double that a decade ago). That is not quite as high as America’s 3.2, but higher than in most of Europe. That may be partly because Chinese people are more likely to get hitched in the first place: the law strongly discourages people from having children outside marriage. Even so, Chinese families are fraying fast.