Obviously, when the RC Church adopted their "celibacy" stance , they were making a mistake. One wonders why a denomination so concerned with tradition would abandon the idea of marriage, which the Apostles endorsed. in any case, that move opened the gates for just such abuse.
It comes from several Traditions. 1 Corinthians, Chap. 7- “Now concerning the thing whereof you wrote to me: It is good for a man not to touch a woman. But for fear of fornication, let every man have his own wife, and let every woman have her own husband… But I speak this by indulgence, not by commandment. For I would that all men were even as myself [unmarried]: but every one hath his proper gift from God; one after this manner, and another after that. But I say to the unmarried, and to the widows: It is good for them if they so continue, even as I…
But if any man think that he seemeth dishonoured, with regard to his virgin, for that she is above the age, and it must so be: let him do what he will; he sinneth not, if she marry. For he that hath determined being steadfast in his heart, having no necessity, but having power of his own will; and hath judged this in his heart, to keep his virgin, doth well. Therefore, both he that giveth his virgin in marriage, doth well; and he that giveth her not, doth better.”
St. Paul clearly identifies the state of virginity or celibacy as a state that is better than the state of marriage. We also see this in the words of Jesus Himself:
Matthew 19: 11-12- “[Jesus] said to them: All men take not this word, but they to whom it is given. For there are eunuchs, who were born so from their mother's womb: and there are eunuchs, who were made so by men: and there are eunuchs, who have made themselves eunuchs for the kingdom of heaven. He that can take, let him take it.”
Jesus is clearly speaking here of those who live singly and chastely for the sake of the kingdom of God. As the Catholic commentary in the Douay Rheims Bible notes about this verse: “There are eunuchs, who have made themselves eunuchs, for the kingdom of heaven... This text is not to be taken in the literal sense; but means, that there are such, who have taken a firm and commendable resolution of leading a single and chaste life, in order to serve God It was taught repeatedly by the fathers of the Church,prominent Christian writers of the earliest centuries who repeated the truths learned from the apostles. Here are two examples:
St. John Chrysostom, A.D. 392: “That virginity is good I do agree. But that it is even better than marriage, this I do confess. And if you wish, I will add that it is as much better than marriage as Heaven is better than Earth, as much better as angels are better than men.”
St. Cyril of Jerusalem, A.D. 350: “While you maintain perfect chastity, do not be puffed up in vain conceit against those who walk a humbler path in matrimony…. Because you have a possession of gold, do not on that account hold the silver in contempt.”
Eucibius, on the other hand said that while God probably loves the effort to live a celibate life, the surely loves those who stay in the world and raise pious and Godloving children.
Toss in the teaching of Augustine about original sin, and his almost heretical view that the flesh is inherently sinful, rather than just weak and prone to sin (ideas not accepted as dogma by the Church in the East, but is accepted by many protestant sects), and it is quite easy to see how the RCC came to the view that priests should not marry, erroneous though it may be.