Abusers are really skilled at putting on a facade for the outside world. It's not a reflection of your comparative worth as a human being, it is a symptom of her disease(s).
Understanding how you got here is going to be a process. For me, I couldn't really begin healing until I was away from the everyday chaos of alcoholism and abuse. That was when I had time and energy to attend Alanon meetings, read self help literature and go to therapy to unravel the mental and emotional knots that were keeping me tied to abusive people and relationships.