The actors met on the set of the 1954 Napoleon biopic Désirée when Rita was just 22, and they went on to date for eight years.
But looking back on the relationship, Rita says she was incredibly mistreated by Marlon — and it drove her to almost end her life.
"Ultimately, it was exciting to be with Marlon. Oh, my god, it was exciting. He was extraordinary in many, many ways, but he was a bad guy," Rita said during a conversation with Jessica Chastain for Variety's "Actors on Actors" series.
She continued, "He was a bad guy when it came to women. I was such a different person then. I had all the makings of a doormat."
As the relationship went on, Rita says Marlon often lied to her, but she knew him so well that she could always tell that it wasn't the truth.
"So whenever he lied, I would look at him and I'd say, 'Marlon, look at me.' And he'd start to grin this kind of — I don't want to use the bad word — that poop-eating grin," Rita shared.
She added, "I could read him like a book, and that's why he loved me, and that's why he mistreated me in so many ways."
Rita admitted that things got so bad that she even attempted to end her own life, in the hopes of getting rid of the sadness she carried.
"I tried to end my life with pills in his house. That’s how I tried to do it. I didn’t understand that if I was going to kill this pathetic, sad, trod-upon Rita, the rest of Rita was also going to go with me. I really didn’t seem to understand that. But that’s what the attempt was. It was an attempt," Rita revealed.
Rita was finally able to free herself from the relationship and went on to marry Leonard Gordon and welcome their daughter, Fernanda.
But years later, she reunited with Marlon on the set of The Night of the Following Day — and he wanted to get back together with her.
"What's interesting is that he wanted to renew. I was now married. I had a beautiful child, Fernanda. He was ready to have a go again. I didn't want that. But he did," she said.
Rita concluded, "He lost a big part of himself, I think. The good part of him, the good Marlon that Rita loved. It was very complicated. Really, really complicated."