Mabel Addis married a man surnamed Mergardt. Information about their relationship, including the date of their marriage and the duration of their marriage, is limited.

Mabel Addis Mergardt passed away on August 13, 2004, at the age of 92. Her death marked the end of a life dedicated to teaching and pioneering work in the field of video games. She left behind a legacy as the first video game writer, whose contributions helped shape the industry.