why one and not the other?

I have detailed memories of one past life that was both bless and rocky. i have found out the true identity of that someone and her family. I would like to know why I have many more memories of a particular someone in the past life and not the other(s). It use to aggravate me because one moment I would have a flashback of them fighting, the other everything was honeymoon-like. It did not follow a straight line. There were much emotions. I think they would be draining each other out in a mental battle of some kind.

Have anyone else figured out, if you have it like me, why one remembers one more so than others and what could be the cause of it? from what i remember from the love there were others that mattered more to her and more stable relationships, at peace-ones.