George and Mildred 1977 S02E06

Episode: The Dorothy Letters. Mildred decides to have a spring clean and turf out some of George's clutter, including his gas mask. She discovers several letters he has written to a woman named Dorothy and fears that he has been unfaithful - though it turns out that they are unsent fan letters to a film actress. Jeffrey decides that the world is over-populated and goes for a vasectomy.