My expat father lost contact with his wife and young daughter after their marriage ended in East Africa in the 1950s. He returned to England and married my mother. As his second family, we emigrated to Perth, Australia, in 1968. My father in those days kept his first family secret, except from my mother.
In the mid-1980s, one evening my mother went to her ladies' public speaking club, visiting a sister club in the hills near Perth.