Advice!! Please help!!!

So There was this guy that I used to have a crush on back in middle school and even in freshman year. He used to date this chick that didn’t like me and the feeling was mutual. Even though I switched schools I always still kind of thought he was cute but was to scared to reach out. They were always on and off. Well my junior year me and this girl ended up at the same school. I made my best friend at this school and she was friends with the girl that dated my crush. Eventually we became friends and I didn’t see this guy anymore as anything but her boyfriend. However after we graduated I left our home town while they stayed. She ended up sort of just leaving our group behind. I’ve tried reaching out in the past and she just never responded or if she did it was short and would end after two or three texts. So I just assumed we weren’t friends. My best friend had told me they fell off too and were no longer close and she hasn’t heard anything from her. Recently her ex and I started talking, but part of me feels guilty even though we aren’t friends anymore. I don’t know what to do. Any advice would help!!!