480. (2) Simple adultery is the adultery of an unmarried man with the wife of another, or of an unmarried woman with the husband of another. By adultery here and in the following discussions we mean licentiousness that is opposed to marriage. It is opposed because it violates the covenant for life established between the partners, sunders their love, defiles it, and closes off the union inaugurated at the time of their betrothal and established at the outset of their marriage. For following the pledge and covenant, the conjugial love of one man with one wife unites their souls. Adultery does not undo this union, because it cannot be undone, but it closes it off, like one who stops up a spring at its source and so prevents its flow, filling its reservoir with feculent and fetid waters. In similar manner does adultery cover with slime and overspread conjugial love, whose origin is the union of souls. Then, when it has been so overspread, there surges from below a love of adultery, which as it grows causes the person to become carnal, and rises up against conjugial love and destroys it. From this comes the opposition of adultery and marriage.