The very fact that you see yourself as a side chick means that you know that the man already has a wife or girlfriend. You are not his number one priority.
You are intruding on another woman’s relationship and may possibly be the home wrecker who disrupt her life and that her children. That is not cool.
You are the secret that his wife or girlfriend must never find out about. It is important for his secret to stay hidden.
If his wife or girlfriend finds out about you, you then becomes his mistake. His explanation to his wife or girlfriend…he made a mistake. You are that mistake.
Of course to save his relationship with the person who really matters he will say you meant nothing. So from being a secret, then a mistake you become nothing. Don’t be his nothing.
The bottom line is you need to respect yourself and respect the other woman’s relationship. If that is not enough remember Karma is a bitch and what you dish out you will get back in return.