I can't believe this... I'm upset that my younger sister told a girl I was seeing about my DUI.
Why you were mad that your younger sister told your girlfriend about your DUI record?
I felt so betrayed by her, I'm going to tell her she is a backstabber.
It's completely understandable that you feel upset at your sister since family is supposed to watch out for each other and not spread embarrassing information about other family members around. Your relationship with the woman you are seeing has been jeopardized because of what your sister has said. You should try to talk with the woman that you are seeing and explain that what you did in the past was a mistake and that you have changed and hopefully she will give you another chance.
Maybe the girl doesn't care.
I hope she doesn't because we all make mistakes in life. And you should tell your sister not to tell people your secrets.