She made a serious error and this is a serious breach of trust. Relationships are based on trust and communication. Do you actually want to stay with her since she's shown she has little self-control? Because her lack of self-control will plague the relationship forever. This is part of who she is and you need to accept that.
You really don't mean anything to her, this is not what someone does when they care about a person.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
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