A long story... very long... like a whole childhood/part of adulthood long years kind of thing.
My sister and I were not raised together. We do, in fact, have different fathers (mine unknown, and hers an abusive alcoholic that passed away some years ago). I have been around my sister a handful of times over the years, nothing that ever made us close or made us "feel" like sisters.
We come from dissimilar, yet similar backgrounds. Some of childhood/teenage years we would like to forget, and there are some areas that either of us could probably never forget no matter how hard we tried. We both saw, heard and lived things as children that no child should ever have to. Which brings me to my next statement.... "That which does not kill you, only makes you stronger." If you grew up in/ever lived in a f'ed up environment, do not perpetuate it by learning to live the same and choose the same behaviors.... choose to be different.
With neither of us having much family of our own, it has been an intriguing year of getting to know each other as adults. We are different, but alike in so many ways. We love each other. We are family.