My husband and I began using NFP about 3 years ago after we attended a retreat put on by our parish and presented (in video) by Christopher West (who is amazing, by the way!). My husband is a cradle Catholic, however I converted about 5 years ago. My husband has never fully been on board about NFP. I think that if you are both passionate about the why of NFP, your marriage will become ever so close, and you should not have a problem using NFP as a reliable method of postponing pregnancy. As for practically, I can only speak for my experience. We attended the CCL NFP classes, as well as the breastfeeding adjunct class. For the most part, NFP worked for us. As long as you are willing to abstain during the fertile times, I believe it works. It is fairly easy to read your body’s signs of fertility after some practice, attending the classes, staying on top of your charting and communicating clearly with your husband (and it helps when he does all he can to help and support you!). We did struggle with reading my body’s signs while I was nursing, even after attending the BF adjunct class. It seems that my body does not always respond in a “textbook” manner, and we found that we had to abstain even more than during “normal” non-BF-ing times, which was hard and frustrating. In fact, we ended up conceiving our latest child during this time, quite by accident. I hope this helps!