When the fading TV heartthrob Park Chul accused his actress wife of infidelity, he ignited an undignified row that has transfixed South Korea and probably mortally wounded the careers of two of the country's top stars. But the best might yet be to come: could Korea's rawest celebrity scandal end a half-century-old law banning adultery?

The scandal began in true tabloid style last October when Park went public with a tirade against his wife, Ok So-ri, who he said had slept with an Italian chef and an opera singer. The accusation was accompanied by lurid stories that the jilted husband, who filed for divorce, had filmed his wife's trysts in a love hotel.

Then the spat took a turn for the worse. Ok stunned Koreans by calling a press conference in which she denied sleeping with the Italian – who she said had only given her English and cooking lessons – but admitted to a short affair with the singer. She then aired intimate details of her sham marriage, leaving her husband feeling, in his words, like a "pedestrian hit by a car". Park responded by filing a criminal suit against his wife for adultery, which is illegal in South Korea.

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The offence, which conservatives say is designed to protect the family, carries a two-year prison sentence, although just 47 of the 1,200 people convicted last year served jail time (most were given suspended sentences). It has stayed on the statute books since 1953 despite at least four legal challenges, but many are wondering if it can survive the fiery Ok, who has petitioned the Constitutional Court to scrap it.

A win would be a milestone in a country where women have, until recently, enjoyed much less sexual freedom than men. Ok and her supporters, including liberal commentators, lawyers and judges, say the state no longer has the right to infringe on sexual relations. "Adultery is an issue, more about sexual desire, to which law cannot be simply applied," said Do Jin-gi, a judge from Seoul, in a statement to the court.

Some of the strongest supporters of the law in the past were feminists, who used it as leverage against adulterous men – most suits are still filed by wronged wives. But some of South Korea's largest women's groups say times have changed and they want it off the books.

An official from the Korean Women's Association told The Korea Times this month that the law was increasingly used by men to take revenge on unfaithful wives. They are pitted against conservative judges and politicians, including the Justice Minister Kim Kyung-han, who said that it was needed "to protect the family and to maintain sex morality and the monogamous system".

Park met Ok on the set of the hit 1994 drama Hero Diary and they quickly earned the popularity of a Korean Posh and Becks. The union produced a daughter, now eight, one of the few times the two made love, if Ok is to be believed. "I had a very lonely and unsatisfied marriage because of a loveless husband," she said. "We only had sex 10 times in our 11 years of marriage."

Not everyone backs the starlet's struggle against the state. The adultery law is popular with the public, many of whom see it as a bulwark against "Western" permissiveness, and even some of Ok's natural supporters, such as young educated women say her behaviour is unacceptable.