Adultery is generally defined as consensual sexual intercourse by a married person with someone other than his or her lawful spouse. In many jurisdictions, an unmarried person who is sexually involved with a married person is also considered an adulterer. The common synonym for adultery is infidelity as well as unfaithfulness or in colloquial speech, cheating. It was also known in earlier times by the legalistic term "alienation of affection".[1]

The sexual partner of a person committing adultery is often referred to in legal documents (especially divorce proceedings) as a co-respondent, while the person whose spouse has been unfaithful is often labeled a cuckold; originally, the latter term was applied only to males, but in more recent times women have been characterized in this way too.

A marriage in which both spouses agree that it is acceptable to have sexual relationships with other people is termed open marriage and the resulting sexual relationships, though still adulterous, are not treated as such by the spouses. Sometimes only one party in an open marriage will opt to have other sexual relationships, in which case the one who does not do so is referred to as a wittol, sometimes called a "contented cuckold".

There have been other varieties of adultery; in Hawaii before the arrival of Christians, twenty-three different kinds were recognized.

Penalties for adultery

Historically adultery has been subject to severe sanctions including the death penalty and has been grounds for divorce under fault-based divorce laws. In some places the method for punishing adultery was traditionally stoning to death.

In the original Napoleonic Code, a man could ask to be divorced from his wife if she committed adultery, but the adultery of the husband was not a sufficient motive unless he had kept his concubine in the family home.

In many jurisdictions (e.g, Austria, Korea, Switzerland, Taiwan), adultery is still illegal, but enforcement of the laws is often uneven. In places where adultery laws are actually enforced, wives are often punished more harshly than husbands, in some cases being considered guilty of adultery even when they have been raped. This has been alleged to happen in Nigeria [2] and Pakistan [3] (see "Honor killings" in "Best Practices").

In the United States, laws vary from state to state. For example, in Pennsylvania, adultery is technically punishable by 2 years of imprisonment or 18 months of treatment for insanity (for history, see Hamowy). That being said, such statutes are typically considered blue laws, and are rarely, if ever, enforced. In the U.S. Military, adultery is a court-martialable offense only if it was "to the prejudice of good order and discipline" or "of a nature to bring discredit upon the armed forces" [4]. This has been applied to cases where both partners were members of the military (and particularly where one is in command of the other), or one partner and the other's spouse. The enforceability of criminal sanctions for adultery is very questionable in light of Supreme Court decisions since 1965 relating to privacy and sexual intimacy, and particularly in light of Lawrence v. Texas, which apparently recognized a broad constitutional right of sexual intimacy for consenting adults.

In Canadian law, adultery is defined under the Divorce Act. Though the written definition sets it as extramarital relations with someone of the opposite sex, the recent change in the definition of marriage gave grounds for a British Columbia judge to strike that definition down. In a 2005 case of a woman filing for divorce, her husband had cheated on her with another man, which the judge felt was equal reasoning to dissolve the union.

Adultery in selected cultures

Ancient Athens

In ancient Athens, the betrayed husband had the right to kill his wife and to punish the offending man as he wished. He was allowed to kill or maim him. Sometimes his limbs or nose were cut off.

Judaism

In Old Testament Judaism a man cannot commit adultery in his own marriage. A married woman engaging in sexual intercourse with another man does count as adultery, and in this case, both the woman and the man are guilty.

According to biblical halakha, where adultery is forbidden in the seventh commandment, the penalty is stoning for both the man and the woman. In practice, often only divorce was the result.