C.T.
I don't have this kind of relationship with either of my sisters or with my brother. But I see this with my mom and her sister. My mom no longer speaks to my aunt and hasn't for many years. She definitely felt a rivalry and also jealous and she thinks so negatively about her sister. It's so sad! I think at some point you should try going to therapy to work through your "sister issues" with a therapist. Another thing to try if that does not help is to tell your sister you really want to improve your relationship with her and you two brainstorm ideas on how to do this. I wonder if "family therapy" would help where you go to therapy together?