Back to the OP.
I agree that their are real differences in sex drive between men and women and that womens sex drive goes down as they get secure in a relationship (provided they were at their peak prior).
I don't agree with their conclusions.
I'll try to explain this in non-scientific terms.
As a man, with a sex drive thats never been higher, I can tell you right now new pussy > old pussy in terms of a turn on factor. Mind you its not 'better' in any real sense, its just you are more turned on by someone new no matter how great your spouse is.
I don't need to save my sex drive for anything, its going to be there, the concept of women 'saving' it for other males like in the original article would imply there is a finite supply.
Now women can and are turned on by the concept of a new partner, this for both the men and women makes genetic evolutionary sense, though it seems to be LESS of a factor for them than for men.
I think that the diminished sex drive would coincide more with having children, something that until the current age of easy birth control would be a given for anyone in a multi-year relationship. Perhaps the lack of drive is more related to that (even in childless couples), where being CONSTANTLY pregnant would cause issues.
In summary.
Mens high sex drive leads them to 'cheat' while still getting it on with their wife.
Womens lower sex drive leads them to raise children and occasionally cheat when someone new triggers it.
Most people posting really have not been in a relationship that long, nor have children yet. No less than 10 years isn't that long.
Give it time ladies