Can I unbestfriend?

I had a guy bestfriend for almost 3 yrs. We have a very clean relationship and it feels like I can't live without him. Until 2017 came and gradually everything has change. We both knew our flaws but it seems like when he knew mine, something change. We are still good friends especially at college but it was unlike before. It feels like we're just classmates/friends now? not a bestfriend thing. lately I knew he was calling someone "bestfriend" too. Am I jealous or what? but it feels sucks. I still try to get back to our old relatioship but he's too busy. Anyway...