Short answers, pulled from the story.
Adultery is generally defined as sexual intercourse between a married person and someone who is not their spouse. Legal definitions vary: New York defines an adulterer as a person who engages in sexual intercourse while having a living spouse; North Carolina defines adultery as when any man and woman "lewdly and lasciviously associate, bed, and cohabit together." The term implies moral condemnation of the act and is not considered a neutral descriptor.
Adultery remains a criminal offense in several U.S. states and is prohibited under the governing law of the U.S. military. Virginia prosecuted attorney John R. Bushey for adultery as recently as 2001, a case that ended in a guilty plea and a fine of $125. Minnesota kept adultery on its statute books until 2023.
Under Islamic law, adultery is called zina and may be punished by stoning. According to a hadith attributed to Muhammad, an unmarried person convicted of adultery faces flogging 100 times, while a married person faces stoning to death. Fifteen countries authorize stoning as lawful punishment, though in recent times it has been legally carried out only in Iran and Somalia.
The Roman Lex Julia de Adulteriis Coercendis of 17 BC punished adultery with banishment, sending the two guilty parties to separate islands, and confiscated part of their property. Fathers were permitted to kill daughters caught in adultery, and husbands could kill their wives' partners under certain legal circumstances. Husbands were also required to divorce adulterous wives.
Adultery laws historically reflected property norms in which wives were legally under their husbands' ownership: the Hebrew word for husband, ba'al, translates directly as owner. Scholar Michael Coogan writes that in the Biblical tradition marriage transferred a woman from her father's property to her husband's, making adultery a violation of property rights. Laws existed primarily to guard against cuckoldry and protect inheritance, so only women's fidelity was typically subject to criminal enforcement.
Kamala Chandrakirana, head of the UN expert body on discriminatory laws, has stated that "Adultery must not be classified as a criminal offence at all." The UN Working Group on discrimination against women has declared that "Adultery as a criminal offence violates women's human rights." Amnesty International has grouped adultery among acts that should never be criminalized, including consensual sexual relations between adults, and the Council of Europe's Recommendation Rec(2002)5 calls on member states to preclude adultery as an excuse for family violence.