Last week, a South Korean condom company and a maker of morning-after pills saw their share prices soaring shortly after the country's Constitutional Court ruled that adultery is no longer a criminal act. Speculators' premature bet? A more "liberal" sexual lifestyle in sight.

The ruling means law enforcement cannot bust into a hotel room to catch a couple having extramarital affairs - once a typical scene when enforcing the law, which was able to put adulterers in jail up to two years.

While declaring the scrapping of the 62-year-old law, the Court cited many reasons. One is the global trend of decriminalization of adultery, which is now confined more or less to just the Philippines and many Islamic countries.

The Court also said the enforcement of the law is ebbing. It is estimated some 100,000 have been punished under the adultery law since 1953. Since 1985, the earliest time the government started tracking the number, about 53,000 people were indicted and 35,000 faced prosecution, while since 2008 among 5,400 indicted, only 22 were prosecuted. Last year, there were no prosecutions.

The law was supposed to protect women. When the anti-adultery law was enacted in 1953 punishing both men and women, lawmakers must have thought it was a significant improvement.

While the history of the criminalization of adultery in the Korean Peninsula goes back to prehistoric times, the purpose of the law had been more or less the same all along to protect patriarchy and keep the "bloodline" intact. For most of the long history of the infidelity law, Korean society punished only the women and their partners in "crime."

The most significant differences of the rulings in 1990, when the first of five Constitutional appeals was made, and last week was how judges saw the significance of the individual freedom and privacy.

The adultery law, the stated purpose of which is to protect marriage system based on monogamy and enforce marital fidelity, infringes individual's right to make decision on sexual matters, freedom and privacy, according the Court's ruling last week.

But in 1990, the Court ruled exactly the opposite way, saying that individual freedom can be restricted in order to maintain orders and meet public interest.

The changes in view in these 25 years reflect the societal changes in South Korea; delayed marriage and increasing number of single households, low birthrate and high divorce rate, a waning patriarchy and obsession with blood relationships, and the empowerment of women.

All these changes are heading to a more mature society where individuals are given more freedom which entails heavier responsibilities.

So, the era after the post-decriminalization of adultery will be a test period to see whether individuals in society can balance the given freedom and responsibility. For now, many South Koreans appear to be still worried.

A poll of 1,000 men and women on the same day the Court's decision was made showed that 49.7 percent of respondents disapproved of the decision while 34 percent favored it.

The tradition of treating adultery as a crime might have gone but infidelity still remains immoral and unethical universally. There is no more jail time but unfaithful spouse might face a bigger financial burden. Unfaithfulness has not previously weighed on deciding alimony or custody in South Korea due to the adultery law, but legal experts and women right groups claim that the country should consolidate measures to compensate wronged spouses and punish adulterers in the civil code.

That might work better than a law becoming a dead letter. After all, financial responsibility is probably a heavier and more effective punishment in the 21st century.

Shares in condom and the morning-after pill companies? They soon reversed the upward trend in the next trading days and fell as people digested the news and more importantly the implications of the change. Extramarital freedom will not be free.

The author is a reporter with the Global Times. gayoungpark@globaltimes.com.cn