What's happening
Two problems. One root cause.
Genitourinary syndrome of menopause (GSM) is the catch-all name for the symptoms you don't see in commercials: dryness, burning, painful sex, more frequent UTIs, and urgency. Up to half of postmenopausal women develop it — and it does not get better on its own.
Separately, but usually overlapping, is the desire problem. Low estrogen blunts arousal. Low testosterone — yes, women have it, and it drops earlier than estrogen — blunts the drive itself. Add in a partner you're snapping at, sleep you're not getting, and pain that makes sex unpleasant, and "I don't want to" becomes a fully rational response, not a defect.
Both pieces are treatable. The local part (dryness, pain) responds almost universally to low-dose vaginal estrogen, one of the safest prescriptions in modern medicine. The desire part often needs testosterone — still routinely underprescribed for women despite strong evidence.