Hey OP here, My ex an I didn't exactly end on good terms which is what was really awful. My ex had actually been seeing the girl for a little while before we broke up. She broke up with me because she had finally decided her new girlfriend was worth leaving me for. I had never met nor cared to who the girl she left me for was. I met my current girlfriend at a coffee shop a few weeks after. This was the first time I was meeting her best friend, and the first time my girlfriend was meeting her best friends girlfriend.