Classic thread. Here is my story.
I have been married for 20 years. The spigot was turned down to a trickle about 2 years after we started having sex ( or about 6 months after the wedding). This seems to be a common theme.
I have tried all of the usual things over the years, with limited and temporary success. She has tried the scheduling thing, with similar results. Current frequency is once every 3-4 weeks. I would prefer 3-4 times/week.
I was a believer in the bait and switch theory for many years, but I now believe this is relatively uncommon, given the findings in the article above (there are a plethora of similar articles and studies out there if you look for them).
Also, there is the concept of transactional vs. validational sex.
I think most people have predominately validational sex early in their relationship, before PNSO. Then, what little sex you have is primarily transactional (duty sex, starfish sex, etc). I think it is hard to consistently fake validational sex. When the stars align, I get validational sex once every year or two, and it is VERY different. It is like the sex you probably had all the time at the beginning of your relationship. For bait and switch to work, a woman would have to convincingly fake validational sex repeatedly, and I think this would be very difficult.
So, the PNSO is likely biological. This realization helped me get over my anger and bitterness. I no longer blame my wife. I’ve come to accept that my wife no longer desires sex with me. True desire cannot be negotiated. It is there or it is not.
For any men contemplating marriage, consider the following:
1. Women lose interest in their monogamous partners much faster than men, typically within two years.
2. It’s not that they no longer desire sex, they no longer desire sex with YOU. If they get a new partner, the libido magically returns.
3. There is little you can do to prevent this. It seems to be hard wired biology. Remember that the success stories you read about here and elsewhere are a small minority of all marriages. The odds are not in your favor.