I Am A Male And My Partner Is A Female

I am a male and my partner is a female age 62. I'm a few years older. We have been together for five years. She obviously went through menopause many years ago yet she continues to have vaginal lubrication as if shs were much younger. I realize this very odd indeed but she now concerned that she may have a medical problem. She has a GYN exam yearly with no abnormalities found. Can you explain her being the exception to the the rule? She also has never taken any hormones. Thank you