when i first learn about it i reacted too. could help to think that it is a relative, to use an example if i know someone was from my past life my mother and she is in this life my child then you can think of it as the old past life identity was/is the child's grandmother or greatgrandmother or something like it.

my biggest shock was when it went from lover to family member, but having gone through past life discoveries it is now something normal to me.

You will calm down about it in time, you just have to adjust =)