107 Thus will it come to pass that the faithful will wholeheartedly thank God that they are bound together by His command and led by gentle compulsion to fly as far as possible from every kind of idolatry of the flesh and from the base slavery of the passions. They will, in a great measure, turn and be turned away from these abominable opinions which to the dishonor of man's dignity are now spread about in speech and in writing and collected under the title of "perfect marriage" and which indeed would make that perfect marriage nothing better than "depraved marriage," as it has been rightly and truly called.
Source: Casti Connubii (Vatican.va)