Ackerman was married to a German-born teacher and translator, Mathilda Wahrman (1912–1990), whom he met in the early 1950s while she was working in a book store he happened to visit. He eventually dubbed her "Wendayne" or, less formally, "Wendy", by which name she became most generally known within SF and film fandoms, after the character in "Peter Pan", his favorite fantasy. Although they went through a period of separation during the late 1950s and early 1960s, they remained officially married until her death: she suffered serious internal injuries when she was violently mugged while visiting Italy in 1990 and irreparable damage to her kidneys led to her death. They had no children of their own by choice, but Wahrman did have a son by an earlier marriage, Michael Porges, who did not get along with Ackerman and would not live in Ackerman's home.