I don't see where Gwynn said anything about this being a "sudden" change in behavior. She did say that he's always been slow...(lucky gwynn! ). But the complete lack of climaxing is more recent...not "sudden".
It IS age related. all of these things are. ED, too, although, that's not what he's got. (from the description). The ravages of time do things to our anatomy.
anyway, google "anorgasmia", and here's the first hit you get:
"...As men age there is a natural slowing down of many physiological processes. "
stress, anxiety, depression are major psychological causes. Gwynn said that he came home the other night with "the weight of the world" on his shoulders. There are physical causes, too, which are related to age. But that is NOT to say that its "normal" for older guys' sexual desire/performance to dry up and blow away at some particular and predictable age.
). But the complete lack of climaxing is more recent...not "sudden". 
