I am happily married now and enjoy sex with DH, but we married late and after some fairly unhappy love affairs when I was in my twenties and early thirties, I opted for celibacy.
I found it much preferable to unhappy relationships.
So I suspect do plenty of other women and men, but as it is not fashionable to be celibate, they don't often admit to it.
Nor do married couples, who have opted for a non-sexual relationship.
I heartily endorse the view that everyone should do what suits them in this respect.
I imagine if I outlive DH that I will happily embrace celibacy again, rather than another person!