I used to believe that 'estranged' meant 'to become strange' and always wondered why women became strange after leaving their husbands, because they always said "so-and-so and his estranged wife".
This lasted until my mid-teens, sadly.
A childhood belief about family

others believed things like this
- I used to believe that my name meant tongue. strange? I think so — Bella
- I used to believe that a widower was a guy who killed married husbands to make thier wife a widow— Jessica
- i used to think that women gave birth to their husbands and marry them...— Pat
- I used to believe that when it thundered, it meant the devil was beating his wife.— Carol
- I always thought that it was "Afully Wedded Wife" Not "lawfully wedded wife"— Sarah
- I used to think that tampons were meant to absorb women's urine so they wouldn't have to go to the bathroom.— Koyaanisqatsi