there is no canonical information in the "Avatar: The Last Airbender" or "The Legend of Korra" series indicating that Mai and Zuko got married. In the original "Avatar: The Last Airbender" series, they were in a romantic relationship, but their exact status at the end of the series was not explicitly defined.
In "The Legend of Korra," which is set in the same universe but takes place several decades later, there is no mention of their marriage or relationship. Keep in mind that new developments or stories may have emerged , so it's best to check the latest sources or official materials for the most current information.