« Last post by Mercyandjustice on Today at 12:35:23 AM »
Mith has the right answer from Pius XI's Encyclical Casti Conubii.Under ordinary circumstances the primary end shouldn't be subjugated. But in extraordinary circumstances, with serious reasons, couples may practice periodical abstinence
Pope Pius XI teaches that there's the primary end of marital relations (procreation) and the secondary (fostering mutual affection, allaying of concupiscence). He explicitly states that if the primary end is not possible (e.g. infertility), marital relations may be had for the secondary ends. The principle is that the primary end can never be positively or willfully excluded while seeking the secondary ends, i.e. that the primary can never be made subordinate to the secondary (which is why IMO NFP is wrong, based on this teaching).