My girlfriend (who's in her 40s) says that when women hit menopause (usually at age 50ish) quite a few find that their libido suffers. But one thing helps lessen the chance of that happening - more sex before hitting menopause.
Yes, I've been busy. It helps, too, for women to masturbate frequently. No wonder 40ish women are known for the upspike with their sexual frequency and cougar adventures.

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