When Tang began to suspect last year that her husband might be having an affair, she was devastated and afraid. The 35-year-old Shanghai resident couldn’t get divorced, property prices in the financial capital would have made it too expensive, and it would have harmed her social standing.

Instead she called the “mistress hunters” to save her marriage. Their business: to exterminate affairs.

“He started to delete his messages and come home late, working overtime a lot. I knew something was wrong,” says the mother of one.

The Weiqing agency employs a team of consultants who convince the mistresses, commonly called xiao san in Chinese or “little third”, to end the affair.

Weiqing, or “protector of feelings”, also does regular marriage counselling, but mistress hunting makes the headlines.

Posing as neighbours, helpers or building managers, the mistress hunters work their way into the confidence of the “little third”.

“Then the main thing we try to do is communicate to them that there are better options available than getting involved in someone else’s relationship,” says Ming Li, a legendary mistress hunter referred to by clients and staff by the honorific “Teacher Ming” to show the esteem in which she is held.

Her job is a bit like being a spy.

“We help people solve problems that occur in people’s love lives. There are many ways to do this. With the mistress, we can use the transference method, where we distract their attention to something else. Or we can organise it so that their jobs get moved somewhere else. Or third, we communicate with the ‘little third’ that the person they’re dating is actually married, which some might not know,” says Ming.

Demand vs supply

“The service has proven so popular, we realised that so many people suffer in their marriages and need help managing their relationships. Demand always exceeds supply,” she says.

Lingering social taboos mean second marriages for women are still far more rare than for men and the stakes are high.

The Chinese language is rich with words for those who have an affair or you yi tui, which translates as “have one leg”, suggesting a leg wrapped around a lover’s. Concubines were outlawed by the Communists after the revolution in 1949 but they are back in a major way, and the number of men with mistresses – er nai (second wife) or xiao mi (little honey) – vastly increased during the fat years of the 2000s.

China had more than 3.84 million divorces in 2015, up nearly 6 per cent on the previous year. The country’s family structure is rigid but, as in other countries, social media make it very easy to have affairs.

An ordinary consulting fee costs about 1,000 yuan per hour (€129), rising to 3,000 yuan (€386) an hour for VIP service. People pay tens of thousands of yuan for the full package. They think it’s worth it.

While technology has made having an affair more convenient, it hasn’t made divorce any less disastrous for women, especially when property prices mean couples cannot afford to split the household. There is even a specific expression in Chinese for people who live together after a divorce because they can’t afford to separate. In most cases, the property will go the family who pay for it, which is often the husband’s family as an apartment acts as a form of dowry.

“With most of our clients, their partner works for a big corporation, or they are not married, or people working in the city away from their spouses, and for them the fee is worth it to save the relationship,” says Ming.

Social standing

Mistresses have extremely low social standing, but compensate for their poor status with incomes and benefits that threaten many family units.

During the daytime in the shopping malls in Shenzhen and Shanghai you see expensively dressed, invariably beautiful young women wandering with shiny Louis Vuitton and Gucci bags, easily identifiable as the xiao san of a business executive who pays their rent and keeps them in such high style.

Despite the highly visible er nai of the first-tier cities, richer wives often turn a blind eye to mistresses as the family can afford it. In poorer households, especially among migrant workers who leave the countryside to work in the cities, it can mean ruin.

Some mistress hunters advertise online that they will beat up the paramour to save the marriage, and are regularly named and shamed on social media, along with videos showing the xiao san being publicly humiliated by avenging wives.

Weiqing has 59 offices across the country, and there are now 300 consultants working for the company, all graduates in law, marriage counselling or psychology.

When people come in, it usually takes one or two hours to win someone’s trust.

“We ask key questions. Someone having an affair is not happy about the current relationship. Instead of solving the problem, they avoid the issue by looking for someone else outside of the marriage, but can the problem be solved if you marry someone else?” says Ming.

Ming is 48, and says the fact she is older than all the girlfriends she befriends to steer them away from the errant husbands is a big advantage.

The government’s highly public anti-corruption campaign has made having a kept woman a less public practice than before, certainly among Communist Party cadres, but the new rich continue to have their lovers and the number who are given expensive apartments as incentives has been blamed for increased property prices in some cities.

“Since President Xi Jinping’s crackdown on corruption there are fewer government officials with mistresses. Mostly our clients now are housewives with husbands who are company executives or businessmen,” she says.

Male wealth

Predictably, it’s nearly always men who stray, as they continue to have the financial power, and the language generally refers to mistresses rather than male lovers. More than 90 per cent of Weiqing’s clients are women and Ming is quite harsh on men who seek help.

“Some men come in for consultation too, around 10 per cent of our client base. Normally those men are weak . . . the men who come here are cowardly and unable to take responsibility, so their wives don’t respect them,” she said.

Ming is not without sympathy for the mistresses, and in some cases has even helped them find new, presumably unmarried, boyfriends.

She tells of one woman who had a thing for older men. The second daughter in a family, she was given away by her family to be raised by grandparents – a fate not uncommon in China where daughters are less prized than sons, and second daughters seen as a liability.

“She always felt abandoned, so would date an older man to feel loved by her father. The things one does when one is young hugely affect adult life choices. We can diagnose what the problems actually are and teach them how to solve them,” says Ming.

Couples therapy

Tang’s own consultations lasted four months and she still consults with Ming occasionally when she has something on her mind and needs advice. She is happy with the way things turned out.

“We both went to couples therapy and figured out what was the problem. He got to express his feelings, complaining how I don’t care enough about him and always pay too much attention to our child. Our relationship had problems long before the affair,” she says.

Chinese family planning laws were changed recently to allow people to have two children, instead of the previous one-child policy, and Tang and her husband are planning to have a second child.

“They did put some pressure on the ‘little third’. I don’t know exactly what they did; my focus was mainly to work with my husband on repairing our relationship. But the affair is over,” says Tang.