Why did madam c j walker get divorced to moses mcwilliams?

Madam C. J. Walker was named Sarah Breedlove when she married Moses McWilliams around 1881 or 1882 in Delta, Louisiana. They had one child and did not divorce. When he died around 1888 of unknown causes, they were still married. Source: Madam C. J. Walker: Entrepreneur by A'Lelia Bundles (Chelsea House/Facts on File)