<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
My ex-girlfriend is going out with my "supposedly" best friend.
<|assistant|>
That is upsetting to hear, as this situation can quickly become complex and difficult to navigate. It could be helpful to talk to your "best friend" to express your feelings and to make sure your friendship is still salvageable. Additionally, talking to your ex-girlfriend might help you to understand why she may have made this decision and to come to an understanding that may help ease the hurt. Ultimately, every circumstance is unique, and so how you approach it depends on the circumstances, but these are possible avenues for consideration.