I wouldn't say its his age alone..... he says since he is older (less horny) that the vaginal area just does have the same pull (thrill) that it had when he was young and in his twenties..... when giving oral sex was the bomb and he was naive to the medical issue / risk that could occur.

He still likes to touch and feel (even use sex toys) - he just doesn't like to put his mouth down there any more... and if he does its a very rare occasion... say once every 6 months.