in 1946 casselman was remarried for a third time after his second wife elizabeth died. casselman was married this time to jean rowe, who was the daughter of earl rowe and his wife treva from newton-robinson, simcoe county. the couple had two children: nancy jean, born in 1948, and william clair, born in 1952. casselman's third wife jean rowe is likely better known by her married name, jean casselman wadds, under which she was known for most of her political career.