i do know that, after working with Otto Preminger in "The Cardinal", he decided to retire from films.
There was also "a scare" in which a well-known Hollywood columnist threatened to "out" him.
He was having a carefully-concealed affair with Casey Donovan.
He did very well as a novelist. So his best days were ahead of him when he quit acting. But it's a shame that his screen career didn't last longer.