She just explained to you how the sex isn’t the most important part. Yet you also stated how for you it still is

Nature is actually part of this so that males can still reproduce even when older. Childbirth was always a major risk for women. It’s only been fairly recent that the risk has been significantly reduced.

Your wife has been trying to tell you that her interest in sex at her age or stage of life is pretty much nil. That’s why she said that if you still want that in your life to get that need met elsewhere.