She was Henry Fonda's first love. They married when very young and working together in a theatrical troupe. After two months, she dumped him for a producer who could help her career. In his autobiography, Fonda wrote of standing in the rain, looking up at the producer's apartment window and seeing his bride there. He forgave her, and almost remarried her ... but she wouldn't have him.
Then she married William Wyler. He's the legendary director who gave us Oscar winners including Jezebel, Wuthering Heights, The Best Years of Our Lives and Funny Girl. He was enthralled but she was done after two years.
Leland Hayward was involved with Katharine Hepburn when Sullavan entered his life. Hayward was Fonda's friend and manager and once he met Margaret, he couldn't resist her. They married when she found she pregnant. 20 years later, their actress/model daughter Brooke Hayward found herself alone with Hepburn, who looked her up and down and apparently still had a hard time accepting this real-live evidence of Hayward's infidelity.
She's on my mind because I watched her today in The Shining Hour. She played the plain girl whose husband is falling for the superglam Joan Crawford. I have no doubt, though, that off screen Maggie could steal any of Crawford's men. Her forehead is too big and round and her nose is too sharp; she's short and her legs aren't great ... and yet in real life, every man she ever wanted fell in love with her!