Meaning of "Who Was That Lady" by Dean Martin

The lyrics of "Who Was That Lady" by Dean Martin seem to be about regret and reflection on a lost love. The singer is filled with curiosity and jealousy about a woman he saw his partner with, wondering if she was special and exciting in a way that he misses. The mention of an angel and the woman keeping her wings hidden could symbolize the idea of the perfect woman who got away. The twist at the end, where the woman is revealed to be the singer's ex-wife, adds a layer of irony to the song. It reflects on how sometimes we don't appreciate what we have until it's gone, and how hindsight can make us see the value of something we once had.