Last week, a South Korean court struck down a national institution: a six-decade-old law that made adultery a criminal act carrying a prison sentence of up to two years. “It should be left to the free will and love of people to decide whether to maintain marriage,” the majority opinion declared. Some 53,000 South Koreans had been indicted and 35,000 jailed for the crime since the government started tracking such figures in 1985. Naturally, the ruling sent the shares of condom and morning-after pill manufacturers soaring.

Adultery bans are a fading but persistent global phenomenon, and they’re instructive when it comes to assessing how sexual and gender dynamics are shifting in different societies. In the United States, for example, adultery laws enacted in the 1700s and 1800s were often prejudiced against women. The laws “were concerned with women cheating on their husbands and having kids that weren’t theirs, and then [the husbands] taking care of kids that weren’t theirs,” JoAnne Sweeny, an assistant professor of law at the University of Louisville, told me. “Adultery could only happen if the woman was married. If the man was married but the woman wasn’t, that wasn’t adultery” but rather the lesser offense of “fornication.” Moreover, “if a wife wanted a divorce, she had to show that her husband lived in adultery, whereas a husband had to show only that his wife had committed a single act of adultery.” As Sweeny has documented, the legal systems in many states continued to treat male and female infidelity differently until the 1950s; as of 2013, at least 18 states still had adultery laws on the books, though they are rarely enforced.

Adultery has been decriminalized in Europe and many parts of Latin America. But it is still illegal in the Philippines, where a married woman can be charged with adultery for any act of sexual intercourse with a man who is not her husband, while a married man can only be charged with “concubinage,” which requires either keeping a mistress at his home or having sex “under scandalous circumstances.” In some Muslim countries whose legal systems rely on or incorporate sharia law, anti-adultery statutes undervalue women’s testimony and can be exploited by men to dispatch with an unwanted wife. The punishments meted out against women accused of adultery can also be severe.

In theory, South Korea’s adultery ban was designed to protect women in a society where men commonly pursued extramarital affairs, according to Kathy Moon, the SK-Korea Foundation chair in Korea Studies at the Brookings Institution. The law was enacted in 1953, the tumultuous year in which the Korean War ended. “You had so many women and men who had lost families ... tens of thousands that had fled from the northern part [of Korea], who had left their families behind ... or lost them in the frenzy and chaos of the refugee flow,” Moon told me. “In that sense, [the law] was an attempt to create order and stability, and, especially for those marrying for the first time, to set a certain standard.” Moon also mentioned the need to move past 35 years of Japanese colonial rule between 1910 and 1945. “For a lot of the value-maintaining elite, they condemned Japanese colonial rule partly for introducing ‘lewd sexual mores,’” she said. The statute was also meant to benefit women in a society with a tradition, at least in elite circles, of men keeping concubines.

Nevertheless, Moon largely rejected the notion that the South Korea’s ban was progressive or protected women. She pointed out that neo-Confucianists lobbied for the law in the 1950s in an effort to reestablish an authentic Confucian social order (last week, a Korean Confucianist organization called the law’s repeal “deplorable”), and argued that the legislation was ineffective and hypocritical. “For many of the elite and the wealthy [men], they were able since 1953 to maintain multiple women and have regular affairs without any kind of social stigma from male society, and for the most part women of the older generation kind of just took it as part of their fate,” she said. In practice, The New York Times notes, the law was often wielded to compel a spouse to accept a divorce or to blackmail married women who had been unfaithful.

If the repeal of South Korea’s adultery law proves to be a net gain for women’s rights, there’s still a lot of work to be done. Although South Korean women have many more educational and economic opportunities now than they did in 1953, major gender inequities remain. In the World Economic Forum’s most recent gender gap report, South Korea ranked 117 out of 142 countries. Only 55 percent of working-age women are employed compared with 76 percent of men, and women are grossly underrepresented in government. Moon said that domestic violence is a massive and mostly overlooked problem, and that immigrant women have recently been arriving in the country as brides, mainly to be used as “child producers.” “These women have very little access to [the] Korean language, they come from relatively poor backgrounds ... their husbands sometimes divorce them without the women even knowing what’s going on,” she explained. If women are being disempowered in South Korea, it’s clearly not just by philandering husbands.