I have written on this here and on a long comment on another blog. Michael is absolutely correct here. As one trained in NFP and having taught NFP, I know that the Church's teaching and intent is that it is a temporary need and only to be used in serious circumstances.
Interesting that this topic has come up of late quite a bit.
Thanks, Michael, for holding up the truth. NFP is Catholic birth-control-it is control of conception.
Dr. Jay Boyd is another source for good teaching.
http://philotheaonphire.blogspot.ie/2013_09_01_archive.html
http://www.ccli.org/
and from that site...
Top 10 myths about NFP
There is a lot of misinformation floating around about NFP and the Catholic Church’s teaching on marriage and sexuality. Do you recognize any of the myths below? Read on to get the “straight scoop!”
Myth #5: If you practice NFP you should use barrier methods during the fertile time “just to be sure.”
Myth #6: NFP is only for good marriages.
Myth #9: NFP is too hard to learn.
Myth #10: NFP is the same as contraception.