Actually, I think women peaking around 40 probably IS a general truth. It is true of all the women I know that they really became much more authentically into sex and enjoyed it a great deal more beginning in their later 30s and continuing on from there.
I don't really understand why you keep asking the same questions, wanting different answers.
There are PLENTY of enthusiastically sexually active women in their 30s, 40s, 50s, 60s, 70s...
Given your W has never really been into sex with you, I see no reason to think that her age or hormones have affected her current interest in any significant way.
