A lawsuit involving a Chinese couple who decided to “go Dutch” on every little thing in their 21 years of marriage has stunned mainland social media.

The couple from southern China’s Guangxi Zhuang autonomous region tied the knot in 1985, and signed a contract to split all costs in half in 2006.

In 2015, they chose to live separately but stay married.

The husband, surnamed Zhang, took his wife, Li, to court in January saying she owed him 110,000 yuan (US$15,000).

Zhang had been listing all the bills he thought Li should share during their 30 years living together, after they separated in 2015.

The expenses included the “thank you fee and nutrition fee” for his vasectomy in 1990.

Zhang also listed the cost of labour when he helped Li repay a loan with her own money, “television and furniture costs” from 1986 to 2015, and “doing extra dishes during festivals”.

Dismissing the husband’s claim, a court in Guangxi acknowledged that the couple had signed a contract in 2006 but said that Zhang could not provide proof that he was owed for the items he listed.

It was also decided that Zhang was being petty and that his behaviour was “against the public order and good morals” and therefore not legally protected.

The court added that couples should help and love each other while building a harmonious family together.

Many people expressed disbelief on mainland social media.

“Why did they not just divorce each other?” one person said on Weibo.

“If he was a tiny bit more of a man, he would not ask his wife to contribute to his vasectomy,” said another.

“It seems they did not love each other at all. I wonder what they would do if one of them became ill or hospitalised?” someone else chimed in.

Another person thought it was “unfair to ask the wife to split the bills, because it was she who gave birth to children.”

“Going Dutch”, or splitting costs evenly, in marriage has become increasingly common in China, as most mainland women continue working after marriage and prefer to stay financially independent.

However, despite many couples working the same hours, women spend more than twice as much time doing housework, according to a Peking University study in 2010.