Alcott was never married. One of Gerwig's remarks to Jo in the film, "I'd rather be a free spinster and paddle my own boat," is really the author's own. The Bhaer in the film isn't much like the one in the page—-not he's nearly as wicked, to use Alcott's term. But they do share one thing: they are both unmarried. However, Jo does marry Mr. March later on in the story. Alcott did marry but she divorced her husband after two years because he wasn't giving her enough time for writing. She had also met someone who was more supportive of her writing ambitions and didn't mind when she wanted to write at night or on weekends. This person introduced her to his friend, who became her second husband. He too was very supportive of her writing endeavors and didn't care when she wanted to write even during the day while working as a teacher. Together, these two marriages lasted from 1857-1873. Alcott wrote about her first marriage in a story called "The Story of an Hour" which was published in the Atlantic Monthly in 1876. This story was later turned into a play called "Little Women". So, yes, Jo March did get married multiple times but only once married would qualify her as "single" within the context of the movie/story.