Why does a 48 year old man not like sex?

Many possibilities: He may be with the wrong partner. The love may have gone out of the marriage for whatever reason. He may have a health issue (a prolactinoma or hemochromatosis are often missed). He may prefer the idealized dead-end world of fantasy images / ideas. And about 1% adults -- male and female -- just don't feel all that romantic stuff is worth the trouble. Is it time for couples counseling?