The other aspect that throws some people is the periodic abstinence.
"You abstain from sex for *how long* every month? No way."
Discussion
Which is an even funnier reaction, when you consider how little sex the average couple is actually having. An astounding number are nearly sexless, even the younger ones.
If you told most guys that they'd be abstaining for X number of days per month, but could have sex every single day other than that, and their wife would probably go along, they'd be like,
Where do I sign up for this program, yo? 🧐
Yeah, cause even the least libidinous wife would know she gets a break at a certain time. 🤣
Plus it encourages couples to bond in other ways when they have to abstain, and forces them to build up discipline in serving each other's needs and the needs of the family.
There's a reason NFP practicioners frequently say it improves their marriages.