I’m not sure how much power you have in this situation. You chose to join a blended family situation. That was your decision. Decisions have consequences. Blended families can be complicated, often because of having to deal with ex-spouses, jealousy, and so forth.
Do what you can to make positive changes. If it means going to therapy, then you might have to acquiesce. If you want to have a relationship with your stepdaughter, you might have to do things that you don’t want to do or don’t think are necessary. That’s all part of attempting to correct these types of issues.
I wish I had better advice for you in this situation, but the reality is it can be difficult for stepparents to affect change. You might suggest family therapy as a way to begin to remedy this issue. Hopefully, that will help. Good luck and please take care.
Dr. Kristina Randle