I have done a lot of research on this. It mostly stems from my last relationship. Also, I have a few very good friends, I mean like, to-Mordor-and-back kind of friends, in this world and they are all connected to my soul family. We have had many lives together and different relationships to each other. One of these friends is extremely psychic and intuitive. No. She's not delusional. She works in neurology, but different tangent, and she confirmed this for me.
My ex thinks we are twin flames and will not let go. We have both seen our past lives together, but they always ended very badly. I think when you have a karmic debt to someone you will re-encounter them over and over. The majority of these interactions are not pleasant, but they have the potential to one day be healing.