In the early Roman Empire, a husband held the jus tori, the right to the bed, which meant that while a wife's fidelity was legally enforced, a husband's sexual relations with slaves or unmarried women were not considered illegal. This legal double standard created a society where the husband's infidelity was often ignored, while the wife's was treated as a theft of property.
The Roman Lex Julia of 17 BC later codified these views, punishing adultery with banishment to different islands and the confiscation of property. Fathers were even granted the right to kill their daughters and their lovers, while husbands were required to divorce adulterous wives.
In England, engaging in adultery with the King's wife, his eldest son's wife, or his eldest unmarried daughter was classified as high treason, not merely a moral failing. The jurist Sir William Blackstone explained that the plain intention of this law was to guard the Blood Royal from any suspicion of bastardy, which could render the succession to the Crown dubious.
There are fifteen countries in which stoning is authorized as lawful punishment, though in recent times it has been legally carried out only in Iran and Somalia. Most stoning cases are the result of mob violence, and while technically illegal, no action is usually taken against perpetrators.
Alfred Kinsey found in his studies that 50% of males and 26% of females had extramarital sex at least once during their lifetime. A 2015 study by Durex and Match.com found that Thailand and Denmark were the most adulterous countries based on the percentage of adults who admitted having an affair.
Adultery can be emotionally traumatic for both spouses and often results in divorce. It can also lead to feelings of guilt and jealousy in the person with whom the affair is being committed, and the correlation between divorces and children having struggles in later life highlights the long-term impact of adultery on families.