People hurt people. Not because they have to, but because they can. The feeling of someone else being in pain that you caused, gives you a sense of authority over them. Some people were hardwired to be misery to others, it amuses them and entertains them. The lack of control in their own lives leads to seeking control in others in any way they can. Some people hurt others in defense. The paranoia of getting hurt makes you do crazy things. Including hurting the people you care about. People conclude that before their loved ones hurt them, they should either escape or hurt them before ending up heartbroken. Instead of believing in them and giving them a chance, they trust their baggage and run away. Running away is always the easier option. Letting your past scare you is giving it credit and power over you, way more than it deserves. But the paranoia is not the only reason you hurt them. Sometimes, you do it because you don't have a choice. It's either you or them. We're after all selfish humans. Living with guilt and hurting someone is easier than getting hurt. Hurting someone is not sane in any world, no matter why you do what you do. There's always an escape to the situation without anyone getting hurt without creating chaos.