You Say Goodbye and I Say Hello

I take on shame about conflicts in my interpersonal relationships. I question what is wrong with me. I am unclear about how much conflict is a reasonable amount. When I am telling a story from my past I feel uneasy when it's time to introduce a character and I say, "...and then So And So who I used to be friends with...". When troubles arise and relationships collapse, is it because of me? Is it them? Is it us? Is that just life? I care about most people's feelings. I am willing to listen, apologize, and often work on changing things about myself. Why, pray god, is my super hero power morphing friends into enemies?