Who is "other" woman ..

I have often been intrigued by expressions like "other women". What do they mean ? What do we imply -- respect, disgrace, anger, approval, admiration or what -- when we refer to a person who has shown guts to get into a relationship with huge social costs as "other woman". In an intellectual philosophical, emotional and poetic sense, who is the "other person" -- other man or other woman. What defines her /his otherness except social norms ? How much store would or should any enlightened mind place by social norms ? Social norms deserve all the respect they get. Is that enough to persecute or ridicule its violation ? And can poetry and societal norms be talked about in the same breath?. Should those who take pride in poetry also take take pride in passionate adherence to societal norms. ? Can societal norms be brought int play whhile discussing higher truths - scientific, spiritual or poetic ? Above all, these are humble questions and must not be confused with arrogant answers or even insinuations....... P L E A S E