Adultery refers to marital infidelity. When two partners, of whom at least one is married to another party, have sexual relations - even transient ones - they commit adultery. Christ condemns even adultery of mere desire. The sixth commandment and the New Testament forbid adultery absolutely. The prophets denounce the gravity of adultery; they see it as an image of the sin of idolatry.
Adultery is an injustice. He who commits adultery fails in his commitment. He does injury to the sign of the covenant which the marriage bond is, transgresses the rights of the other spouse, and undermines the institution of marriage by breaking the contract on which it is based. He compromises the good of human generation and the welfare of children who need their parents' stable union.
Adultery is punished by death for both the man and the woman involved. But in a concerted effort to limit culpability for the death penalty, the Rabbis limited adultery to the case of a married woman having sex with a man who is not her husband, or a man having sex with a woman married to another man. If a man, married or not, has sex with a single woman, this is not classified as adultery but rather as a way for the man to take a wife-even another wife, for until the decree from Rabbenu Gershom in the tenth century, polygamy was allowed.
Traditional Christianity understands the union of husband and wife as the uniquely appropriate locus for (1) the realization of sexual companionship, (2) reproduction, as well as for (3) the satisfaction of sexual desire. Because of this uniqueness, it can be concluded that it is forbidden to make other persons partners in reproduction, as well as for (3) the satisfaction of sexual desire. Because of this uniqueness, it can be concluded that it is forbidden to make other persons partners in reproduction. One may not allow third parties to enter reproductively into the union of husband and wife. So, for example, the use of artificial insemination by a donor or the use of donor ova is adulterous in this very important sense: a third party would be brought into the unique and sacred reproductive intimacy of husband and wife, which no one should separate.
The third principle of universal sexual morality is that spouses should be faithful to one another. Certainly this principle has always been more honored in the breach than in the observance for the simple reason that the animal side of human nature is promiscuous. But the fact remains that the faithfulness of both spouses throughout time, has been considered the ideal of marital conduct. You may search through all the great literature of the world and you will find no words extolling marital infidelities. While it is true that the “sins of the flesh” have always been more readily forgiven to husbands than to wives, all human societies have taken a very harsh view of men who seduce—or rape—the wives or daughters of the men of their own society. When the Trojan, Paris, ran off with Helen, wife of the Greek King Menaleus, Greece fought a seven-year war against Troy, to protest the seduction and abduction of Helen. King David’s abduction and seduction of Bathsheba, the wife of Uriah, the Hittite, scandalized his court. It also caused that God-fearing monarch great agonies of repentance. In passing, King David’s repentance produced some of the world’s greatest poetry—perhaps, an early proof of Sigmund Freud’s theory that all the creative works of man—all his art, poetry, architecture, even his proclivity for moneymaking, political power, and Empire building, are au fond, sublimations of his consciously or subconsciously repressed sexual desires.
Clare Boothe Luce, “Is the New Morality Destroying America?” May 28, 1978
Adultery is a meanness and a stealing, a taking away from someone what should be theirs, a great selfishness, and surrounded and guarded by lies lest it should be found out. And out of meanness and selfishness and lying flow love and joy and peace beyond anything that can be imagined.
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 preservation 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 adultery." And by the words of Christ: "Whosoever shall look on a woman to lust after her has already committed adultery with her in his heart." The force of this divine precept can never be weakened by any merely human custom, bad example, or pretext of human progress, for just as it is the one and the same "Jesus Christ, yesterday and today and the same forever," so it is the one and the same doctrine of Christ that abides and of which not one jot or tittle shall pass away until all is fulfilled.
