I think that it means that his lover died, by whatever means, and he knew she always was the one, and he loved her forever, he still loves her and never wants to say goodbye, but he has to cause she's dead. But he will still love her even if she's dead and will never love anyone else for the rest of his life, and one day when he dies they'll meet again and be together forever. Well that's just what I think it means lol.