Is it normal to believe in someting like reincarnation?

I understand that my thought process on this subject is controversial to most of the mainstream population, but I've read some posts on here which kind of make me want to express a POSSIBLE theory to some of these dilemmas (despite the perverse nature of some of these posts and the fact that some of these posts could have been created by what is known as a troll). I've read a lot of posts on incest with close relation and older men/women feeling an intense, instant attraction, to someone that is younger, attractions to friends, ect. And this is where my theory ties into the title of this post, I have a belief that everyone is the world is born to learn a certain life lesson and people/situations (whether good or bad) are put in front of us in order to learn these life lessons before we die; however, after death our souls are kept in a type of heaven/purgatory until we are reborn again in order to either relearn the lesson that wasn't learned from the previous life or to learn a completely different lesson, and at times we encounter some of the same people that we knew from the life before, but they have also been reincarnated into a different person ect. Um...for example I read a post on here about a woman who is romantically/sexually involved with her brother and the two have had children together, but despite how perverse I think this situation is, I often wonder if there is a possibility that these two individuals could have been lovers in their previous lives (and unrelated by blood), but in this life the two were born related to each other in order to learn a different life lesson, but the feelings that they had for each other in their previous lives ended up being carried over with them into this life. Is it normal to think this way (please note I am not trying to justify what these people or any other person does (especially in their private time)), and is there anyone out there who shares reincarnation/reincarnation-like beliefs too?