From Corinthians we see:
1 Corinthians 7: 4-5
4 A wife does not have authority over her own body, but rather her husband, and similarly a husband does not have authority over his own body, but rather his wife.
5 Do not deprive each other, except perhaps by mutual consent for a time, to be free for prayer, but then return to one another, so that Satan may not tempt you through your lack of self-control.
From Pope John Paul II:
John Paul II also says that if the only reason a couple is having sex is to transmit life, then they may be in danger of using each other rather than loving each other (see Love & Responsibility p. 233).
Also, John Paul describes the “beatifying experience” of conjugal union as a foretaste of the joys of heaven (see TB, Dec 16, 1981 and Jan 13, 1982). In Love & Responsibility, by his detailed discussion of the husband’s responsibility - out of authentic love for his wife - to see that she achieves sexual climax (see Love & Responsibility pp. 270-278).
CCC States:
V. THE GOODS AND REQUIREMENTS OF CONJUGAL LOVE
1643 "Conjugal love involves a totality, in which all the elements of the person enter - appeal of the body and instinct, power of feeling and affectively, aspiration of the spirit and of will. It aims at a deeply personal unity, a unity that, beyond union in one flesh, leads to forming one heart and soul; it demands indissolubility and faithfulness in definitive mutual giving; and it is open to fertility. In a word it is a question of the normal characteristics of all natural conjugal love, but with a new significance which not only purifies and strengthens them, but raises them to the extent of making them the expression of specifically Christian values."152
The unity and indissolubility of marriage
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."153 They "are called to grow continually in their communion through day-to-day fidelity to their marriage promise of total mutual self-giving."154 This human communion is confirmed, purified, and completed by communion in Jesus Christ, given through the sacrament of Matrimony. It is deepened by lives of the common faith and by the Eucharist received together.
1645 "The unity of marriage, distinctly recognized by our Lord, is made clear in the equal personal dignity which must be accorded to man and wife in mutual and unreserved affection."155 Polygamy is contrary to conjugal love which is undivided and exclusive.156
- The fidelity of conjugal love
1646 By its very nature conjugal love requires the inviolable fidelity of the spouses. This is the consequence of the gift of themselves which they make to each other. Love seeks to be definitive; it cannot be an arrangement “until further notice.” The "intimate union of marriage, as a mutual giving of two persons, and the good of the children, demand total fidelity from the spouses and require an unbreakable union between them."157
1660 The marriage covenant, by which a man and a woman form with each other an intimate communion of life and love, has been founded and endowed with its own special laws by the Creator. By its very nature it is ordered to the good of the couple, as well as to the generation and education of children. Christ the Lord raised marriage between the baptized to the dignity of a sacrament (cf. CIC, can. 1055 § 1; cf. GS 48 § 1).
III. THE LOVE OF HUSBAND AND WIFE
2360 Sexuality is ordered to the conjugal love of man and woman. In marriage the physical intimacy of the spouses becomes a sign and pledge of spiritual communion. Marriage bonds between baptized persons are sanctified by the sacrament.
2361 "Sexuality, by means of which man and woman give themselves to one another through the acts which are proper and exclusive to spouses, is not something simply 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 woman commit themselves totally to one another until death."143
"The acts in marriage by which the intimate and chaste union of the spouses takes place are noble and honorable; the truly human performance of these acts fosters the self-giving they signify and enriches the spouses in joy and gratitude."145 Sexuality is a source of joy and pleasure:
2364 The married couple forms "the intimate partnership of life and love established by the Creator and governed by his laws; it is rooted in the conjugal covenant, that is, in their irrevocable personal consent."147 Both give themselves definitively and totally to one another. They are no longer two; from now on they form one flesh
Check out the Christopher West, Books on Theology of the Body. Great resource for helping a couple through issues like these.
Bottom line is, if your wife has some physical ailment, try and find out the cause as “1ke” suggest. She has made a vow to God and you to be a partner in Holy Matrimony, if she consistently and repeatedly breaks that vow of her own free will, she is sinning and destroying your marriage of her own accord.
