The greatest care should be taken lest the human conjugial be destroyed by inordinate and immoderate fornications: care must be taken, in every way, that this be preserved, since the conjugial is the very jewel of human life, and the repository of the Christian religion (1804-1806 [CL 456-458]).

With those who for various reasons cannot yet enter into marriage, and who on account of salacity are unable to govern their lust, that conjugial is kept in existence by taking a mistress (1806, 1807 [CL 459]);