Welcome
Hopefulbuthurtin!
Let me start by welcoming you. I'm sorry for the hurt that has been caused when your step mom entered the picture. It is tough. To be alienated by your own flesh and blood is so painful, yet it is a sad part of having a BPD in your life. Have you read much about BPD yet? How did you find out about our site? You will find a lot of supportive help here.
One of the possible things going on could be triangulation in which your dad took the side of your step mom and now you are on the out side or the victim.
Escaping Conflict and the Karpman Drama TriangleAfter reading this article, do you think this is what may be happening? I can certainly understand your not wanting to apologize for something you didn't do. It is hard to know how to advise you, but perhaps after reading some of the other posts here or when other members post to your questions, hopefully we'll get some good thoughts for you.
Here is one more link for you that I hope will be helpful:
BPD BEHAVIORS: ProjectionPlease continue to post and let us know how you are doing!
Wools