I have been with my girlfriend for about a year now, and a few months into the relationship she revealed that she had voices. They were just voices though, couldn't control the body only comment on things that we're going on. I was at first shocked but did research and came to terms, and actually became friends with them. But just last week a new one has shown up. She was an abuse victim and I'm not sure if that's where this is coming from. The new one started off just in her nightmares. He has been there for a few years now. He would reenact the abuse scenes and torture/rape/whip her. That was bad enough but she could escape it when she woke up, and through a few sleeping medications. But now he's manifested into (what it seems to be, this is what I'm not getting) into an Alter. He now controls the body and causes her to self harm, which he's never done before. He also doesn't have a name, he just identify's as a "Nightmare." He shows her scenes of me hitting her and is trying to separate us. When she comes back in control she knows it's not me but is still shaken up. I'm trying to help but I haven't felt with this before. The other voices have tried to take control of the body, but they are somewhat weak and not able to really move around. Their dexterity is off, and it just looks messy.

Is there a way to stop him, or get him to stop? Unlike alters I've read about they are extensions of her personality, this one just seems pure evil. I'm not sure if we can talk to him, and my girlfriend absolutely will not go to a doctor (she was absurd by a therapist before) so I am really not sure where to go from here.

Thank you for listening and hopefully giving me some insight.