Is it possible...not to be interested in sex at all?

I’ve known a female friend of mine for several years, and she’s always said that since her last boyfriend and her finished (8 years ago), she is just not interested in sex anymore. At all. With anyone or anything. She’s told mutual friends the same thing.

Is this possible? As a red-blooded (married) man with a high libido, I find the concept hard to believe/understand.