If you don't mind my asking --- and if you don't mind telling: (1) Calendar or Sympto-thermal? (2)Were you trying to achieve, or to avoid pregnancy? (You can do it either way with NFP) (3) Your kids: all in all, are they a plus or a minus to your family and your life?
Again like I said, I'm not prying. But I'm always interested in honest experience.
It was 17 years ago when I started having babies, the calendar was about all there was or all we knew of. While my Catholic husband insisted I practice NFP he then used the old he wasn't getting enough so he screwed around alibi.