I have the same problem expect its with myself. I have major trust issues. I am engaged to a good man. I have been abused and abanoded in the past. My dad left when I was young and my sister's dad who adopted me drinks a lot. My mom smokes pot everyday. I have never really had a stable home. I don't trust anyone. I can say from experience that giving her time to trust you and not yelling when you get in fights really helps. If you yell at her when you fight she will break down. She will get scared. Also when your fighting don't ever hang up on her that will just feed into her trust issues. The best way to deal with it when she gets scared or paranoid is find out why she is scared or paranoid and say "Babe I love you and I want to help you through this if you don't want to talk right now I understand but when you are ready to talk I am here for you." It may take a while for her to open up to you but trust me it will help to make her trust you more. If you come off as caring and understanding it will really help.