Is it normal to believe in alternate dimension versions of people?
Let me give you an example: Alan Rickman and Severus Snape. When you look at them and their life's history, they seem like 2 completely different men but in actuality, they're alternated versions of each other. Alan is to this world as Severus is to his world. I believe that regardless of who you are, there will always be a different (but still very similar!) version of you in another realm. Therefore, you'll always live on somehow ("True Death" is non-existent).