You should go back and re-read Felder's book if that's your impression. I just finished my second time with it and he clearly talks about doing cocaine and how he did have extra marital affairs. The very first paragraph of the book talks about how the all had white rings around their noses as they opened the show with Hotel California in the 70's.
"We could hear the rumble of the crowd in the dressing room. It sounded like a thunderstorm brewing somewhere far above us. As we emerged one by one from the bowels of the stadium, our lips wet with beer, white powder rings around my nostrils, the rumble grew louder and louder."
Later on he talks about how a groupie he'd been with sent him a letter through the fan club, his wife read it and it almost ended his marriage. That's just a couple of examples of the many times he talks about both issues openly.