Serious question: Do you believe women ever want to have sex after 6 months, or after 2 years in a relationship?

I ask because I've always experienced a drop-off in her interest around that point in 15 years of dating.

Plus, I have no friends in long-term relationships where the woman seriously wants to have sex after that point.

It would seem that things are only worse now. This article reveals that this woman, and none of her friends, are having sex -- despite her claiming to be attracted to her "lover" https://www.nytimes.com/2020/07/09/parenting/sex-parents-coronavirus.html

I would be genuinely curious about your answer. It would seem to make sense evolutionarily that a woman's sex drive for a specific partner would decrease after 6 months (enough time to get pregnant) or after 2 years (enough time to raise a child out of infancy).

Again, I don't mean to come off as an "incel" (involuntary celibate) person, but I've repeatedly had experiences where the woman's libido (for me specifically) suddenly disappears in a relationship. And I've never even heard of the opposite situation, so I'm quite curious about it.