Although attitudes differ widely between cultures, and even between neighbouring communities, almost all consider adultery an offence, the punishment for which may be divorce or banishment, public exposure or mutilation, even death. Adultery is specifically defined as the act of sexual intercourse between a married person and someone other than his or her spouse, whether or not the other person is also married. In a broader sense, the term applies to an act of sexual intercourse with a partner outside the permitted group. Some communities permit adultery but only under certain conditions. Local law often discrimates between male and female, higher class and lower class adulterers, and female adulterers are often discriminated against.
Attitudes towards adultery are changing, especially in industrialized countries. More married women are now having affairs. Increasingly, women, not men, are the first to stray from marriage. In both the USA and the UK, 25 to 50% of married women have at least one lover after they are married in any given marriage. From 50 to 65% of married men stray by the age of 40. Whereas for people who married before 1960, women waited 14 years (and men 11) before having an affair, in 1989 women wait 4 years (and men 5). Currently 73% of married people claim to have had at least one affair. Death by stoning is prescribed by Islamic laws in the event of adultery.
Adultery is damaging to the good of the family and is a direct betrayal of the most sacred of human relationships.
It follows therefore that they are destroying mutual fidelity, who think that the ideas and morality of our present time concerning a certain harmful and false friendship with a third party can be countenanced, and who teach that a greater freedom of feeling and action in such external relations should be allowed to man and wife, particularly as many (so they consider) are possessed of an inborn sexual tendency which cannot be satisfied within the narrow limits of monogamous marriage. That rigid attitude which condemns all sensual affections and actions with a third party they imagine to be a narrowing of mind and heart, something obsolete, or an abject form of jealousy, and as a result they look upon whatever penal laws are passed by the State for the preserving of conjugal faith as void or to be abolished. Such unworthy and idle opinions are condemned by that noble instinct which is found in every chaste husband and wife, and even by the light of the testimony of nature alone, – a testimony that is sanctioned and confirmed by the command of God:"Thou shalt not commit adultry," and the words of Christ: "Whosoever shall look on a woman to lust after her hath already committed adultery with her in his heart." (Papal Encyclical, Casti Connubii, 31 December 1930).