Photographer Eve Arnold, a co-worker of Capa’s and friend of Isabella’s, recalled in the book Magnum Cinema Isabella’s account of how Ingrid told her about her relationship with Capa.

“When Isabella’s mother was writing her autobiography, she was very worried about what her children would think of what she wrote on her affair with Robert Capa. One evening, when Isabella was about to go to bed her mother threw her the manuscript, saying: ‘Here you are. Read it but don’t think too badly of me!’ Isabella said she could not wait and stayed up all night reading it. The next day she said to her mother, ‘It’s incredible that you had such a lover.’”

Isabella expanded on learning about this relationship in an essay she wrote for the catalog of Magna Brava: Magnum’s Women Photographers, an art exhibition at the Scottish National Portrait Gallery. Here’s an excerpt from her essay from the NY Post:

“Most of it (the autobiography) I already knew, with the exception of one event. Mother had been in love with Robert Capa. They had a passionate affair. But Bob did not want to marry. He knew he was going to die in one of those terrible wars he photographed (and indeed he did, in Indochina in 1954, killed by a land mine).”

“I was stunned”, she says of the affair. “Bob Capa had been one of my heroes. His friend Chim Seymour was often at our house, photographing all of us. Chim’s photos are, for me, the memory of my family at one of its happiest moments, when Mom and my father, Roberto Rossellini, were still in love.”
Isabella thinks her mother was attracted to both men through their work. “Dad’s films were like Bob’s stills in motion.”