Mr Yu Feng bought a ticket to Hainan last year, checking into a resort for a week. There, he made friends with the owner, a well-spoken woman in her 20s, telling her that he just wanted to get away after his company folded.
A few days later, in the middle of a round of drinks, she overheard him getting into an argument with a female cousin on the phone.
"You need to leave him," Mr Yu huffed. "You won't find happiness as a mistress."
But in reality, there was neither a cousin nor a failed business. Mr Yu was on an assignment - and the owner of the resort was a real-life mistress he had been hired by another man's wife to thwart.
"The story of my 'cousin' was supposed to mirror hers," Mr Yu told The Sunday Times. "She was meant to hear it. I wanted to show her that there can be no satisfactory end to this story."
Welcome to the world of China's xiaosan quantuishi, or "mistress dissuaders", a growing sector in a country which has seen divorce rates rise for 12 years straight, reaching 3.6 million cases last year.
Analysts say many divorces today are sparked by extramarital affairs, typically between wealthy older men and young single women.
Marriage counsellor Deng Ling, for instance, said the proportion of clients who see her because of mistress problems has risen from 20 per cent a decade ago to more than 80 per cent now.
As a result, in the past five to 10 years, marriage counselling firms started discreetly offering "mistress dissuading" services.
"This is one of the problems of China's rising affluence," Ms Deng told The Sunday Times. "Previously, people didn't have money. Now, rich men think having a mistress is something to be proud of."
Dissuaders are usually trained in counselling or psychology. While not new, this sector burst into the spotlight only recently, after Chinese media reports highlighted the unusual yet lucrative occupation.
The job is a mix of private detecting and counselling.
Those in the business told The Sunday Times that while there is no magic formula, they have to first persuade the straying husband to save the marriage.
Then, playing the role of a compassionate outsider, they contact the mistress, gain her trust and convince her there is no future in the relationship. The dissuaders may or may not reveal their identities.
Given the difficulty of the task, the process can be lengthy.
"But many mistresses are also lonely and willing to talk if you befriend them," said Ms Ming Li, who heads an agency in Shanghai with a staff of 30. "Their lives revolve around one man, and they might be shunned by their friends and family."
To persuade the mistress to leave, they may offer money, get in touch with her family, or even introduce her to another boyfriend, she said.
The Chongqing-based Mr Yu claimed a high success rate - more than 90 per cent - because his agency, which employs 30, accepts only viable cases, where both the husband and wife are open to saving their marriage, he said.
"In cases where the romance is dead, devoid of physical or emotional intimacy, the couple are better off divorced," he added.
But their services do not come cheap. Clients of Mr Yu and Ms Ming pay at least 100,000 to 200,000 yuan (S$21,800 to S$43,600) each, excluding expenses.
They field hundreds of inquiries over the phone but accept just two to five new cases a month - with each one taking three months to a year to resolve. Almost all their clients are from China.
But the trade has attracted controversy as well, with critics questioning its ethics and effectiveness. Several Chinese media commentaries have slammed these companies for their high fees and for "treating the symptom, not the disease".
Ms Ming, however, said they always counsel the couple, even after getting the mistress to leave. "That's the most important part, although 'mistress dissuading' has grabbed the headlines."
But Mr Yu, who has been a marriage counsellor for 15 years, conceded that the industry needs regulation, saying: "More and more firms are claiming to offer these services just to earn a quick buck, when they have no experience in counselling."
As for the woman resort owner he met in Hainan, he eventually talked her into leaving her married lover - 15 years her senior - with the help of his imaginary "cousin".
"She never told me she was a mistress, but she saw herself in my 'cousin'. She's bright, but wrongly believed the man would leave his wife," he said.
"Eventually they broke it off. She never found out who I was."