C. 4. Good of fidelity: "In the very act in which married partners pay the debt they owe to each other, even if they demand this somewhat intemperately and without self-control, they owe equal fidelity to each other."D. 5. Marriage requires (1) permanence, and (2) openness to children.Status of marriages with various problems with sexDesire for sex without desire for children is made better by the fact of being married with the one with whom one desires sexE. 6. Fidelity extends not only to having intercourse for the sake of children, but to the spouses weakness. One shows fidelity, even if the request for sexual intercourse comes from weakness and incontinence. Venial fault is connected with marital intercourse for the sake of lust.F. 7. For Christians, fidelity must be kept even in the event of divorce. Remarriage is not possible, even for the sake of procreation. The strength of this bond is on account of the "sacramentum" of a greater reality. The Romans, however, do allow the woman to remarry. "The initial marriage covenant is so clearly bound up with a kind of sacrament that it is not made void even by the act of separation... the bond of fellowship between spouses is so strong that though they were bound together for the sake of begetting children, the marriage is not dissolved even in order to beget them" (ch. 6-7).

But, when fidelity is employed to commit sin, we wonder whether it thought to be called fidelity.However, whatever its nature may be, if even against this something is done, it has an added malice; except when this is abandoned with view that there might be a return of the true and lawful fidelity, that the sin might be amended by correcting the depravity of the will. For example, if anyone, when he is unable to rob a man by himself, finds an accomplish for his crime and makes an agreement with him to perform the act together and share the loot, and after the crime has been committed, he runs off with everything, the other naturally grieves and complains that fidelity had not been observed in his regard. In his very complaint he ought to consider that he should have observed his fidelity to human society by means of a good life, so that he would not rob a man unjustly, if he feels how wickedly fidelity was not kept with him in as association of sin. His partner. Faithless on both counts, is certainly to be judged the more wicked. But, if he had been displeased with the wickedness which they had committed and so had refused to divide the spoils with his partner in crime on this account, that he could return them to the man from who they were taken, not even the faithless man could call him faithless.