Eleven years into their marriage, in 1994, her husband started staying out overnight instead of returning home.
Madam Zhu, 54, a farmer in south-western Kunming city in Yunnan province, who would give only her surname, said she heard he was having an affair and had been infected with a sexually transmitted disease.
Still, she was devastated when her husband left home in 2010, leaving her and their teenage daughter to fend for themselves.
He has rejected Madam Zhu's repeated requests for divorce.
Public aid lawyers told her she needed evidence of his infidelity to get the courts to approve her case, Madam Zhu told The Sunday Times.
It means victims no longer need to suffer in silence, social groups have the legal basis to intervene if necessary, and the police can handle it as criminal offences.
LAWYER WANG BEIBEI, explaining the significance of the new law.
"My mental state has been poor after all the stress over the years. People tell me that my ordeal is not considered domestic violence, and I have to be physically abused to be covered by the law," she added.
"But mental abuse can be worse than physical abuse over a long period of time. I hope the new anti-domestic violence law would help raise my chances of getting a divorce and a fresh start."
For many like Madam Zhu, China's first law against domestic violence, passed on Dec 27 and set to go into force on March 1, is long overdue.
The law considers psychological harm inflicted by family members part of domestic abuse.
Data from the All-China Women's Federation shows that about 25 per cent of Chinese women suffered violence in their marriage, with 40,000 to 50,000 complaints received yearly. Of the cases in 2014, some 90 per cent involved husbands abusing wives; the rest involved abuse of children and the elderly.
Lawyers and non-governmental organisations say the actual situation might be worse, with most victims keeping their abuse under wraps as it is seen as shameful for the family in traditional Chinese culture.
In fact, less than two decades ago, physical abuse was not acceptable as grounds for divorce in China.
Though the Marriage Law was amended in 2001 to ban domestic violence, many victims found little help from the authorities, which are reluctant to intervene unless serious injury is inflicted.
The push for legislation intensified in recent years after several cases raised public awareness.
For instance, celebrity entrepreneur Li Yang, who founded the Crazy English learning programme, was exposed in 2011 as having abused his wife, Ms Kim Lee, after she posted photos of her bruised face on China's Sina Weibo portal.
There was widespread public anger after Mr Li admitted to the abuse but blamed his wife for disclosing family affairs to the public. The couple divorced in 2013, with Ms Lee getting alimony and compensation.
"We were very emotional when the law was passed, as it is the result of our hard work over the past 20 years," Ms Li Ying, head of the Beijing Yuanzhong Gender Development Centre, told The Sunday Times, referring to the newly passed domestic violence law.
But the law has drawn mixed reactions.
Supporters note the importance of the law for legally defining domestic violence as a criminal offence, which gives the authorities power to take action against perpetrators. The law defines domestic abuse as "physical, psychological and other harm inflicted by family members with beatings, restraint or forcible limits on physical liberty, recurring invectives and verbal threats".
"This law means domestic violence is no longer a family affair but a criminal offence," Beijing-based lawyer Wang Beibei of Yingke Law Firm told The Sunday Times.
"It means victims no longer need to suffer in silence, social groups have the legal basis to intervene if necessary, and the police can handle it as a criminal offence."
Observers also applaud the authorities for improving the legislation by expanding coverage to psychological abuse and also to those who are not related but living together, such as cohabiting couples.
Changes were based on feedback received after a draft was released last August for public consultation.
"The goal of the draft was to preserve family stability. Now, the top priority is to protect the safety of the abused persons, which is the correct order of priorities," said Ms Li.
Also crucial is how the law empowers other parties, apart from the victims, to report alleged abuse, say observers. For instance, employers are obliged to reprimand employees over domestic violence and mediate family disputes, while legal guardians and close relatives, along with grassroots organisations and women's welfare groups, are allowed to report abuse too.
Another key feature is how the law spells out the process for approval of personal protection orders. Courts must decide on such applications within 72 hours. Decisions must be made within 24 hours for urgent cases.
However, critics slam the law for not going far enough and not covering sexual violence, especially marital rape.
Lawyer Lu Xiaoquan at Beijing's Zhongze law firm, who has worked on domestic violence cases for 15 years, said failure to identify sexual abuse in the law will make it even more difficult for victims to stand up for themselves.
"It implies that people can do whatever they want in intimate relationships, and that some sexual offences might be immune from punishment," he was quoted in a report by the Washington Post.
Gay rights groups have also criticised the law for not explicitly stating whether it covers homosexuals, citing remarks by senior legislator Guo Linmao that "people who cohabit do not include homosexuals".
Yingke's Mr Wang said the lawmakers may have left it vague as Chinese society has not reached a consensus on homosexual relationships.
"The law is more conservative to fit the reality. But as societal values change, I believe the law will soon take into account marital rape and homosexual violence," he added.
For now, there is widespread acknowledgement that the law is not enough to curb domestic violence due to the social stigma of exposing one's family problems publicly.
Official data backs this up. China's deputy chief justice Huang Ermei was quoted as saying at a conference last July that victims would go to the police only after suffering an average 35 instances of abuse.
Also, only 500-plus personal protection orders were issued across China from 2008 to 2014, either because few were aware or confident of these legal provisions, or that the courts were reluctant to handle and approve them, say observers.
Going to the authorities is the last thing on the mind of Madam Li Guirong, 70, despite the tension with her daughter-in-law. Both got into a fight two years ago. Madam Li, a native of north-eastern Liaoning province, was injured in the face.
"I can't move out because I have no money to buy my own property. Also, most elderly live with their sons, so if I move out, people will know about my family problems.
"If things worsen, I'd rather move to a shelter than report to the police," she told The Sunday Times.
China Daily newspaper's senior writer Xin Zhiming wrote in a commentary on Dec 31 that non-governmental organisations should be encouraged to play a bigger role in handling domestic violence.
"They can offset the inadequacy of the government's anti-domestic violence agencies, which are often short of hands and funds," he said.
Another Kunming farmer, who wanted to be known only as Madam Zhang and who was abused in her two previous marriages, believes the real solution is public education so society recognises domestic violence as an act not to be condoned.
Madam Zhang, whose first marriage of 17 years ended in 2010 after years of physical abuse, said her second husband broke her leg in a beating in 2013. Scores of villagers witnessed it, but no one helped her.
Madam Zhang, who managed to get a divorce, said: "The society is now too cold and selfish. But also, the lack of education is a factor.
"To those women suffering from domestic violence, I would say: 'Live with dignity and for yourself.'"
•Additional reporting by Carol Feng