I find such studies to be so flawed and full of holes and assumptions you can drive a truck through them. This study is making an implied connection between women’s age and sex drive. That could be only coincidental. The real factor affecting sex drive could be a host of other issues that only come into play over time, thus the appearance that age is some sort of predictor.
The bigger danger, and one I have had to confront, is that people like these types of studies because they can serve as ammunition to back up their argument against their spouse. It becomes another stone in their defensive wall and justification to hold onto resentment. That leads to self delusion, and eventually narcissism.