1 Corinthians 7:3
3 The husband should fulfill his marital duty to his wife, and likewise the wife to her husband. 4 The wife’s body does not belong to her alone but also to her husband. In the same way, the husband’s body does not belong to him alone but also to his wife. 5 Do not deprive each other except by mutual consent and for a time, so that you may devote yourselves to prayer. Then come together again so that Satan will not tempt you because of your lack of self-control.
The section on Marriage in the Catechism says this:
1644 The love of the spouses requires, of its very nature, the unity and indissolubility of the spouses’ community of persons, which embraces their entire life: “so they are no longer two, but one flesh.” They “are called to grow continually in their communion through day-to-day fidelity to their marriage promise of total mutual self-giving.”
It is referring to Familiaris Consortio, which says this:
Consequently, sexuality, by means of which man and woman give themselves to one another through the acts which are proper and exclusive to spouses, is by no means something purely biological, but concerns the innermost being of the human person as such. It is realized in a truly human way only if it is an integral part of the love by which a man and a woman commit themselves totally to one another until death. The total physical self-giving would be a lie if it were not the sign and fruit of a total personal self-giving, in which the whole person, including the temporal dimension, is present: if the person were to withhold something or reserve the possibility of deciding otherwise in the future, by this very fact he or she would not be giving totally.
Also, Casti Connubii says this:
- The second blessing of matrimony which We said was mentioned by St. Augustine, is the blessing of conjugal honor which consists in the mutual fidelity of the spouses in fulfilling the marriage contract, so that what belongs to one of the parties by reason of this contract sanctioned by divine law, may not be denied to him or permitted to any third person; nor may there be conceded to one of the parties anything which, being contrary to the rights and laws of God and entirely opposed to matrimonial faith, can never be conceded.
- By this same love it is necessary that all the other rights and duties of the marriage state be regulated as the words of the Apostle: “Let the husband render the debt to the wife, and the wife also in like manner to the husband,” express not only a law of justice but of charity