(1926 - 1933) (divorced) (1 child)
He served in the German Army during the First World War and afterwards, in 1926 married Vera Bythiner (31 March 1904 – 30 September 1942), who was born in Posen in Imperial Germany (now Poznań, Poland). The marriage produced a son, Werner Peter Pfeffer (3 April 1927 – 14 February 1995), then the couple divorced in 1932. Fritz was granted custody of the boy and raised him alone until November 1938, when the rising tide of Nazi activity in Germany persuaded him to send him into the care of his brother Ernst in England. Werner emigrated to California in 1945 after his uncle's death and changed his name to Peter Pepper, later establishing a successful office supplies company under that name.
The tide of antisemitism in Germany, which increased from the election of Adolf Hitler in 1933, forced most of Fritz's relatives to flee the country. His mother had died in 1925; his father remarried and remained in Germany, only to be arrested; he died in Theresienstadt in October 1942. His elder brother Julius Pfeffer had died in 1928, Emil Pfeffer emigrated to South Africa in 1937, Ernst Pfeffer moved to England and died in 1944, and Hans left for New Jersey. Their sister Minna remained with their father in Germany and died in Nazi custody. Vera escaped to Holland but was arrested in 1942 and died in Auschwitz.