So one of my best friends told me that she cheated on her boyfriend last night. She was at her house & got super drunk & her brother had some friends over. One of her brothers friends carried her to bed & she told me that she thought it was her boyfriend. Anyway, while he was carrying her she kissed him on the lips. She feels terrible but I know how terrible it feels to be cheated on. I'm unsure if I should tell her boyfriend or persuade her to tell her boyfriend herself. I'm not sure what to do. Advice would be great :)