I think there's a difference between extended mourning and "fantasy." Is it actually fantasy? Like do you believe the two of you are in love or anything like that? Or are you grievinh heavily and missing him? I don't think either is "normal" in thr sense that it's definitely been long enough that it's really sad and painful that it hurts so badly... But not that it's necessarily "fantasy." i know that I personally have a really difficult time with endings and feeling abandoned and just missing someone to the point of agony for a really long time, but I think it has more to do with lack of security and depressive rumination than "fantasy." I horribly miss the relationship and love I had for my T but I know that she hurt me and it wouldn't be safe for me to go back... So no fantasy there. I really think HOW you are thinking about him matters. But, either way, that you need help and not judgement.