I understand your concern. As I wrote earlier, it is important that you protect yourself from any more abuse, that you make yourself unavailable for more. If it takes no contact, make it so, is my suggestion.
If you are indeed close with your stepbrother, if he is close with you, the two of you will be able to remain close regardless of your mother input to him, I am thinking. The two of you can agree to not talk about her and continue your closeness.
You mentioned seeing a therapist. I hope you do. It is difficult to start adulthood when the adults in your life so far failed you. And they failed you. Yet healing is possible for you and your motivation to get better is evident.
To everyone thanks for all the support, and love be with you all. I have had ups and downs. I fell into an abusive relationship which ended around a month ago. I lost a lot of mutual friends as they did not believe anything that I said, there were a lot of untrue rumors spread about me by my previous partner. All my mutual friends took her side even though I was nothing but kind and supportive. I do not take the role of victim often, but in this case I was used and it drained all my energy again. It unfortunately left a blemish on an otherwise positive period. It’s been hard to lose so many friends and for them to assume that because I am a man that I must be in the wrong. But other than that I am happy to read your messages things have mostly been positive and things look up <3
I am sorry to read that you were in a recent abusive relationship and that your friends assumed you were in the wrong and your ex girlfriend in the right because you are a man and she is a woman. I sure hope you get to know the next woman in your life thoroughly, make sure she is honest and treats you respectfully, not abusively. As you are with her. Glad you posted again, more than a year since you stated this thread.