Robert Evans said,
“Mia came to me and said, ‘I have to leave this move and return to Frank. I love him’.
"I took Mia to a screening room and showed her an hour of edited scenes from Rosemary’s Baby. I said, 'Mia, you're a shoe in for an academy award'. Suddenly, she wasn’t so interested in Frank.”
Mia was served divorce papers from Sinatra on the set of Rosemary’s Baby. She cried all the time, losing weight which ironically helped her characterization of Rosemary. She was nominated for a Golden Globe, but not an Academy Award. Sinatra hired Jacqueline Bisset, to replace Mia.
Both movies were released the same week, with The Detective grossing well at the box office, but with Rosemary’s Baby grossing five times more.
Robert Evans said,
“Mia came to me and said, ‘Please buy a two-page spread in Variety with The Detective grosses on one page and my movie’s grosses on the other page, side by side.’ I said, 'I can’t do that, Mia.' Hell has no fury like a woman scorned.”
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At the time, I couldn't understand why Mia, so young, would be interested in Frank Sinatra. But from what I just read, he was marrying her for business, probably because having her around made him look younger than he was.
Ron