Ancient Christian Sexual Thought by P. Sherrard.
Yet in spite of the fact that marriage is recognized as a sacrament by the Church, the attitude of Christian thought towards the sexual relationship and its spiritualizing potentialities has in practice been singularly limited and negative. From the start Christian authors have been ill at ease with the whole subject…
early Christian theologians did not hesitate to affirm that celibacy is per se superior to marriage; and, second, they have seemed incapable of envisaging any aspect of sexuality other than its purely generative (not to say genital) expression, and towards this they display an antipathy obsessive to a degree scarcely less than vicious. Although precluded by their basic doctrine from subscribing to an out-and-out dualism in this matter, and so from attributing the origin of sexuality directly to an evil power, their practical attitude differs little from that of dualists of a Manichaean type. Sexuality is tainted. It is impure.
He had also made it clear (I Cor. VI: 16) that for man and woman to become one flesh and so to conform to the symbolism of the union of Christ and the Church they had to fulfill the act of coition. When this symbolism was regarded as conferring on marriage a sacramental dignity—and St. Augustine himself believed this to be the case—the fact that marriage could acquire this dignity and so its indissolubility only through such a consummation continued to be accepted virtually without question. This placed Christian theologians [EO and Rome] in an untenable position. They were obliged by scriptural authority to accept that the procreation of children was an end good in itself and that by becoming one flesh man and woman partook of a “great mystery” and possessed the sign of a supernatural union; yet they were persuaded that the act which determined both procreation and this sacramentum is tainted with evil.