Article II. On the Properties of Matrimony, Namely, its Unity and Firmness

757. • The unity of matrimony is situated in this: that matrimony is the union of one man with one woman.

1. It is certain that polyandry is opposed to the natural law, because it is opposed to the principal ends of matrimony, namely, the generation of offspring and their good education. - Thus all.

2. It is certain that simultaneous polygamy is prohibited in every case, at least by the divine positive law of the New Law, as is evident from Luke 16:18: Everyone who dismisses his wife and marries another commits adultery. It is likewise established from the Council of Trent, session 24, canon 2.

3. It is certain that second and further marriages are licit both for a man and for a woman, even under the evangelical law. This is established from the authority and practice of the Church, as well as from Sacred Scripture, 1 Corinthians 7:39: A woman is bound by the law as long as her husband lives; but if her husband has fallen asleep, she is free: let her marry whom she wishes, only in the Lord.

A twofold firmness of matrimony is distinguished: the one regards the bond, the other the bed.