I recently finished reading a book by Henry Bushkin, who was Johnny Carson's lawyer for about 15 years. Carson used to make jokes about him in his monologue, calling him Bombastic Bushkin. Somehow he got connected with Carson and they got along well for about 15 years then Carson got pissed at him about something and fired him.
Anyway, one of the first things Bushkin did after getting hooked up with Carson go with Carson and some other guys to an apartment Carson's wife was keeping in NYC. Carson suspected his wife of cheating on him so they were doing some sleuth work. So they bribed a doorman to get in the building then somehow into the apartment and snooped around and they were right, Carson's wife was having an affair and pictures they found made it clear that the guy she was having an affair with was...Frank Gifford. (I don't mean to give the impression the pictures were sex pictures. They were just regular pictures.)
Bushkin said Carson was demolished, weeping, etc. But of course, throughout the book it makes clear that Carson cheated left and right on his various wives. It didn't give a lot of details but just made clear he cheated a lot. He was a very volatile guy. He was usually easy going but could quickly get very angry, especially when he was drinking. Carson was a mean drunk.