Misdirected Anger

What is it that causes us to take anger at ourselves and turn it against others?  Especially against people we supposedly love and would want to protect. 

I have spent a lot of time doing this.  Most of my life, in fact.  And now, having been confronted with that fact and having been hit over the head with it so hard that I can no longer deny it.  So how do I find a new way to live?  And how do I convince my former victims that I will not turn around and do it to them again?

I need to find out who I am now.  And then I need to learn how to be the new me.