Girlfriend is not alone.....so not alone! I remember how I felt when I realized the exact same thing. I was EMOTIONALLY drunk when I chose my now ex husband. I made my pretend husband up in my head and super imposed him on this crazy, addicted, controlling, racist, self-centered man. Dang! I was really good at pretending - everyone else saw it but me.
I quickly discovered that as sick as my husband was I actually feel sicker....I'm the one that chose a man addicted to crack and wild sex. What was I thinking? Actually, I wasn't.
I can't tell you the best way to handle your situation. I know that what has helped me was working the program that I wished that he would work. I went to counseling. I prayed. And I kept doing the next right thing. And now today we've been apart for a little more than 5 months. I'm re-creating my life. Not easy stuff but I've grown a whole lot through all of this.
Try not to be hard on yourself....it takes what it takes and you can only do better when you know better.