Elysium, my dear, yes, I have had something similar happen. I don't know what else to say. My T helped talk to those involved, particularly the one who abused another alter. Probably most of us have what are called introjects of our abusers, just a fancy Freudian term for and alter who is modelled on the behavior of the abuser. It's complicated, why we do that, but identifying with the one who had power was part of the survival. That alter is stuck in a role that is harmful. Your T can help this part learn something different. I understand how hard and shameful this can feel to talk about, so you are very brave to bring it here where probably others besides you and me have had similar experiences. I'm sorry that you have to deal with it. I hope that knowing you are not alone will help you. Aside from getting help from your T, you can write or talk to that part and say how you feel, say it is not okay and must never happen again, that abuse is forbidden. I hope that part is reading this. It is not a condemnation of you, only the behavior, and it is time to learn to behave in other ways.
Take care of yourself Elysium, this experience will likely tire you, zap your energy. PM me if you wish. if safe