South Korea was one of only three Asian countries, along with Taiwan and the Philippines, to criminalise infidelity - about 5,500 people have been convicted since 2008.
Around the world, adultery raises mixed feelings ranging from criminal offence to an acceptable practice. So where is adultery illegal? And what are the punishments?
Adultery is defined as sexual relations between a married person and anyone except their spouse.
The recent leak of user data from cheating website Ashley Madison not only exposed millions of people as unfaithful partners, but also, legally speaking, as criminals, depending on where they live.
All European nations have decriminalised adultery. But while it is not considered a criminal offence, it may still have legal consequences, especially in divorce proceedings.
Adultery is illegal in 20 states in the US, typically as a misdemeanour. But in several states, including Idaho, Massachusetts and Michigan, it is a felony. Prosecutions are rare, and usually involve just a fine.
Around the world
In February, South Korea's top court ruled that adultery is no longer a crime, revoking a 1953 law under which cheating spouses could be jailed for up to two years.
Countries governed by Islamic law, including Saudi Arabia, Pakistan and Somalia, strictly prohibit adultery. Prosecutions are common and punishment can include fines, imprisonment, flogging and in extreme cases, the death penalty.
In 2008, a female 13-year-old rape victim was stoned to death by 50 men in Somalia under the government's strict adultery laws.