Evil twin...

I believe my mother gave birth to twins; one good, the other evil.  The evil one has grown to be twice my size and beats on me regularly; he wants me to self destruct by isolating myself from others, treating them with indifference when I am around them, sabotaging all relationships (current & future), down-grading any achievements, my failures are reasurred not my accomplishments.  He constantly tells me I've over-achieved; minor mistakes he punishes me & tells me how stupid I am, how ugly I am - he even tells others to also treat me as if I'm ugly & unattractive!  I'm no good, incompetent and that I only deserve a life of punishment, lonliness, despair & constant disappointment.  He tells me if there is a God, why hasn't he rescued me yet; that he must not love me or think I'm not worthy enough to be saved. 
I have been busted up and bruised emotionally all my life; I've never learned to love myself or have any confidence that I can overcome my abuser.  It's taken its toll on me and I've been a slave to his prophesies.  When he tells me I can't, I won't; if I try and fail, he says I told you so and I won't try again.
He finally tells me the only way to get rid of him is too kill myself; and I believe him...