[quote=askeptic]I wouldn’t be surprised if the divorce rates for NFP couples were extremely low, but I think it is erroneous to conclude that NFP leads to good marriages.
I think it’s fair to say that only very conservate Catholics use NFP (I think most Western Catholics use birth control). They obviously use NFP for religious reasons, and those same religious reasons prohibit divorce.
If they are faithful to the Church to the extent of not using birth control, it only makes sense that their faithfulness would extend to not divorcing.
For all we know, they could have horrible marriages and stay together simply because divorce is a sin. (Not saying that this is the case, just that it could be and still produce the same statistics.)
The moral is that correlation is not the same as causation.
While you are correct that we should be wary of drawing a causal link where none exists, with NFP I believe there is one. Consider this: couples practicing NFP correctly must actually discuss and both be apprised of days of fertility and infertility. For most couples, this topic isn’t an easy one to discuss at first, certainly not in the detail required for NFP. My husband is an obstetrician, and I still get a bit uncomfortable talking about mucus! Increased communication will lead to a stronger marriage, you cannot but agree. And similarly, no one person in the relationship is passing off the responsibility for family planning on the other. Both are responsible for the knowledge and decision-making. Further, you can see a clear causal link between increased relations and NFP: you know when it’s the “right” time, depending on your intention to conceive or delay, and that’s almost as good as pencilling in a date (or 21). Increased marital relations=better marriage. In addition, in truly practicing NFP, the couple is instructed to pray before deciding whether to try to conceive or delay. Increased mutual prayer surely leads to better marriage. How can you argue with that? Further, in learning more about NFP, a couple is almost likely to increase in their faith, as they read about and internalize the theology behind it–self-donative love, the dual purpuse of the marital embrace, etc. Stronger faith life will lead to better marriage.
I had one more thought, but my kids are running wild and I lost it! I do think there are people who go into marriage really up on their knowledge of the theology of the body and the Church’s position on contraception, and such persons can hop right into NFP with full understanding of the whys and the comfort of great faith to soidify their marriage, my experience has been the opposite: as I and the vast majority of devout Catholic friends I know have gone through married life, we have increased in faith and thereby sought knowledge to more fully live out the teachings of the Church, and in doing so, embraced NFP because of the reasoning and instruction behind it. We have become more orthodox Catholics because of NFP, not the other way around. This is antecdotal, to be sure, but it is true for every couple I know.