"Bogart had been happily married to Bacall for nine years, he wasn't a casual womanizer. His self-control where women were concerned, thought Bacall, puzzled and fascinated Frank. "He just didn't understand how a man could be not only talented but so intelligent, and also have a family and not fuck around. He just didn't understand how anyone could do that, because all he did was fuck around". Frank Sinatra was "wildly attractive, electrifying", "there must have always been a special feeling alive between Frank and me", said Bacall.
Singer Frank Sinatra and actress Lauren Bacall attend a party for the musical 'Pal Joey' on October 10, 1957 in Los Angeles, California.
Peggy Connelly suspected that Frank and Bacall began an affair before Bogart died. "Frank loved Bogart", she said, "but this woman was just something else". The affair with Peggy would last for much of 1957. Frank even proposed again, but she again declined. She wanted to pursue her singing career, moreover, and he did not want her to work.
Bogart did not know about his wife's "real relationship" with Frank, Verita Thompson said. The actor William Campbell, however, thought Bogart had been uneasy on that score. "That's the way I picked it up... Because there was some relationship there, more on her part than his. And I think Bogart was aware of it". Bogart was still worrying about it only months before he died.
Gene Kelly, Frank Sinatra and Kathryn Grayson in "Anchors Aweigh" (1945)
In January 1957, in his last hours of full consciousness, Bogart watched Frank's 1945 movie Anchors Aweigh on television. When he died, thirty-six hours later, Frank was in New York playing the Copacabana. He canceled performances and locked himself in his room, avoiding calls from everyone except Bacall". -"Sinatra: The Life" by Anthony Summers (2006)