21 Joseph then was not the less His father, because he knew not the mother of our Lord, as though concupiscence and not conjugal affection constitutes the marriage bond. Attend, holy brethren; Christ's Apostle was some time after this to say in the Church, “It remains that they that have wives be as though they had none.” And we know many of our brethren bringing forth fruit through grace, who for the Name of Christ practise an entire restraint by mutual consent, who yet suffer no restraint of true conjugal affection.
Yea, the more the former is repressed, the more is the other strengthened and confirmed. Are they then not married people who thus live, not requiring from each other any carnal gratification, or exacting the satisfaction of any bodily desire? And yet the wife is subject to the husband, because it is fitting that she should be, and so much the more in subjection is she, in proportion to her greater chastity; and the husband for his part loves his wife truly, as it is written, “In honour and sanctification,” as a coheir of grace: as “Christ,” says the Apostle, “loved the Church.” If then this be a union, and a marriage; if it be not the less a marriage because nothing of that kind passes between them, which even with unmarried persons may take place, but then unlawfully; (O that all could live so, but many have not the power!) let them at least not separate those who have the power, and deny that the man is a husband or the woman a wife, because there is no fleshly intercourse, but only the union of hearts between them.
Source: Sermons on Selected Lessons of the New Testament (New Advent)