§ II. On adultery

494. Definition. - Adultery is copula had with a married person.³

Principles. - I. Adultery is a most grave sin, both against chastity and against justice. This is clear: 1° From Scripture:¹ If a man sleeps with the wife of another, each shall die, that is, the adulterer and the adulteress; and you shall take away evil from Israel. ... Neither adulterers shall possess the kingdom of God. 2° From reason: for adultery violates in a grave matter the right of another, namely of the other spouse; it obstructs the good of offspring; it harms the family; often it begets scandals and quarrels, and produces innumerable other evils, as daily experience teaches.

II. Adultery committed with a married woman is a graver sin, of itself speaking, than if a married man were to sin with an unmarried woman. The reason is that in the prior case copula either harms generation (which happens not rarely), and then the husband is unjustly deprived of children; or it introduces false heirs into the family, or at least often begets uncertainty of offspring.²

Note. - 1° It makes no difference that the spouse consents, because such a cession of right is null, since the right over the body of the spouse belongs to each not only for the private good, but also for the public good. Hence this proposition 50 was proscribed by Innocent XI:³ "Copula with a married woman, with the husband consenting, is not adultery."

2° If a married man sins with a married woman, there is a twofold adultery; which must be expressed in Confession.

3° He who knows his wife sodomitically, by the common opinion more probably commits adultery; because this is against the good of the faith given, and this circumstance must be declared in Confession.³