Why are girls so indifferent and cold when you confront them for hurting you?

I’ve been in some situations where I’m talking to a girl and she’s acting like I’m the only guy she wants and everything is going great and then I find out they’re talking to someone else behind my back and when I confront them for this. On several occasions they don’t act remorseful like they’ve done anything wrong they just act cold and indifferent.
Why are girls so indifferent and cold when you confront them for hurting you?
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