As a teenager at boarding school in the mid 1950s, DH's uncle found that clothing, bedding and laundry thereof were managed by the staff of the "Linen Room". Every Friday evening, each boy found on his bed a "laundry bundle", containing one each of flat bed-sheet, pillow case, shirt, vest, underpants and pair of socks; alternate Fridays saw a pair of pyjamas as well. The sheet was intended to last two weeks, the first on top, the second on the bottom, and the PJs for two weeks in succession. The remaining intimate garments were intended to last a week, with the option, rarely exercised, of drawing further items from the Linen-Room store if absolutely necessary.
According to DH, almost everyone in his uncle's dormitory of some thirty boys went commando under their PJs, with no forced ventilation or air conditioning!
Is this the sort of environment that inspired your DH's preferred night attire? And having "spilled the beans", as it were, on DH, what about your own good self?