You think it would be bad to try adding a ex friend on social media?

So my ex girlfriend pretty much killed my relationship with my best friend. I have sent said friend messages in the past about how hurt I was that she wasn’t there for me during my break up with my ex after saying she would be. I have been thinking of adding her back on social media to see if she would accept my friend request. She was following me on 3 different social media sites but I blocked her everywhere since I was hurt. I just heard from a mature friend that she no longer wants at our old job think she was fired I don't know.
You think it would be bad to try adding a ex friend on social media?
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