371. (9) In married partners who love each other tenderly, jealousness is a just anguish in accord with sound reason, that their conjugial love not be sundered and thus perish. Every love carries with it a fear and anguish - a fear of its perishing, and anguish if it does. The same is true of conjugial love, only its fear and anguish are called zeal and jealousness. Such a zeal in married partners who love each other tenderly is just and in accord with sound reason, because it is at the same time a fear of losing eternal happiness, not only one's own, but the partner's as well, and because it is also a protection against adultery. As regards the first point, that it is a just fear of losing eternal happiness, both one's own and one's partner's - this follows from everything we have presented previously concerning truly conjugial love, and from the fact that from conjugial love comes the blessedness of their souls, the happiness of their minds, the delight of their breasts, and the pleasure of their bodies. And because these continue for them to eternity, it is a fear for the couple's eternal happiness. That such a zeal is a just protection against adulterous affairs, is obvious. On that account it is like a fire blazing out against any encroachment and protecting itself against it. It is apparent from this that anyone who loves his partner tenderly is also jealous, but justly and soundly so, in the measure of the man's wisdom.