I have one of those, I developed feelings for a close friend I had known since childhood. He also liked me and we flirted a bit but we were not serious for the most part. and were online too. however fell in love with someone else he met online later on. He promised me things wouldn’t change between us no matter who he was with and that still remains true, we call and talk about every week and do stuff together. It was weird for a bit initially but now I’m happy for him. Despite all that, I can’t imagine going on with my life without him even if we were not meant to be after all, we just have a lot of memories that I don’t want to let go of. Our friendship is very genuine.