11 Throughout the book I have made many remarks in a tone of great moderation on virginity, widowhood, and marriage. But for the sake of brevity, I will here adduce but one passage, and that of such a kind that no one, I think, will be found to gainsay it save some one who wishes to prove himself malicious or mad. In describing our Lord's visit to the marriage at Cana in Galilee, after some other remarks I have added these: “He who went but once to a marriage has taught us that a woman should marry but once; and this fact might tell against virginity if we failed to give marriage its due place— after virginity that is, and chaste widowhood.
But, as it is only heretics who condemn marriage and tread under foot the ordinance of God, we listen with gladness to every word said by our Lord in praise of marriage. For the Church does not condemn marriage, but only subordinates it. It does not reject it altogether, but regulates it, knowing (as I have said above) that 'in a great house there are not only vessels of gold and of silver, but also of wood and of earth; and some to honor and some to dishonor. If a man, therefore, purge himself...he shall be a vessel unto honor meet...and prepared unto every good work.'” I listen with gladness, I say here, to every word said by the apostle in praise of marriage.
Do I listen with gladness to the praise of marriage, and do I yet condemn marriage? The Church, I say, does not condemn wedlock, but subordinates it. Whether you like it or not, marriage is subordinated to virginity and widowhood. Even when marriage continues to fulfil its function, the Church does not condemn it, but only subordinates it; it does not reject it, but only regulates it. It is in your power, if you will, to mount the second step of chastity. Why are you angry if, standing on the third and lowest step, you will not make haste to go up higher?
Source: Letters (New Advent)