I’m not clear as to what extent your comment is intended to be a clever, humorous remark, but I do think it reveals something that may be getting lost in this discussion.I’m still waiting for a fertile catholic couple to live out this fantasy of a healthy active sex life and no kids.
It would have to be very, very rare for a faithful, doctrinally orthodox Catholic couple, adhering to the magisterium, with no grave reasons to avoid having children (“we just don’t want children, we like our life the way it is, and we want to have the joys of marriage unhindered by the responsibilities of raising a family”), to use NFP to try and achieve this end. It is a “contraceptive mentality” in the extreme, even if morally acceptable means are used.
People who want to live this way, usually make very aggressive use of contraceptives, or go ahead and have themselves (one or both partners) permanently sterilized. It’s not a mindset you associate with magisterially loyal, faithful Catholics. It is just the “Catholic thing” for marriage and the begetting of children to be two things that cannot and should not be deliberately separated. This hypothetical couple who is willing to use NFP with the goal of lifelong childlessness, joyfully embraced, with no other reasons than “we just don’t want children”, seems to me to be so far-fetched as to be virtually a “straw man”.
Put another way, if a couple wished to share this goal with fellow Catholics — “we’ve decided not to have any children, and yes, we use NFP — there’s nothing ‘wrong’, neither of us is sick, or gay, or mentally ill, or anything like that, we just like the childfree life” — they would get some very strange looks from these fellow Catholics. For that matter, a couple living a Josephite marriage — assuming they ever shared this fact with anyone — would get some strange looks as well. People generally don’t “get” sexless marriages.