The biggest reason we don't use contraception is most forms are actually abortion inducing such as the pill and iud,
I can say and I don't know why but my wife is much more interested in me since we stopped using contraception
Most forms are
not abortifacients. Most forms either are estrogenic compounds which prevent ovulation or are methods that prevent sperm from migrating.
And yes, sometimes those estrogenic compounds drive down libido - which could be why your wife is more interested now that she's off it.
Abstinence within marriage in 100% effective
natural family planning is 95% effective better than birth control
95 percent is not 99 percent, and the link you provided shows 95 percent effective
at ensuring conception. That's... not what we're talking about here.
Both sets of my grandparents never used contraception and only had 5 and 3 kids each it doesn't mean you are having 15 kids on the other hand my mother in law was 1 of 15 and the 17 of them lived in a 900 square foot house in Oklahoma they all did fine
The cost of living has gone up - inflation is an ugly thing.
Assuming this family was to grow up in the US in a populated area - lets use the northeast as an example, here's a bit of a reality check. We're talking at least 15-20 grand a year on food. That's not including water to take a 2 minute cold shower (you can forget about hot water), or medical deductibles for child care. If there is any kind of transportation cost to get to work, then it drives the costs up further.
You'd have to be making at least 50k a year gross income, and that's to just barely scrape by, and only if you didn't have to deal with housing costs. If housing was involved, the minumum is going to be closer to 75-100k, and again just scraping by. The food you (and your children) would eat will not be very good (or very nutritious, which is
bad for children), nor will it be very plentiful (also bad for children). Medical care will be nonexistent or extremely basic (also
bad for children), and clothing (if you can even afford it) is going to be threadbare and of minimal protective value.
So how exactly is the average American supposed to feed and clothe 15 children without relying on taxpayer dollars to keep their children form starving to death.
They can't, which means in your scenario a married couple should have sex until they have had as many kids as they can afford, at which point, their marriage is completely devoid of sex.
That's a pretty tough sale, isn't it?