What do you do when your Mom has issues with you?

My mother and me do have the best relationship and anytime we argue she brings my dad, her ex into it. They have been divorced for over 25 years! She believe that my relationship with him should be the same as my relationship with her. The only differences my dad does not interfere in my life. Ex: My relationship with my dad's mother has never been good because this woman would make such bad comments about my mother I couldn't stand. The last straw was when I was she called me and evil lying child because I defended my mother and out of all of her grandchildren I was the redhead stepchild made to do everything. I would go to mother and tell her what my grandma did and her answer was the same each time "I wasn't there". I don't know about ya'll,but if my child comes to me crying about something their grandma did and you know this person has a bad history with you from jump it warrants you checking it out. My mother never did and she brings this up with me if we have any arguments about anything which is silly because she then say "why don't I act this way with your dad?" For one thing my dad apologize for his mother actions and I did not know this until recently that my dad talked to her about this. I explain to my mother before that she never defended me on this, but let me get hurt and tell me to get over it. Mind you all my friends think the world of my mom, which is fine I just don't have that type of mother and daughter relationship with her. I love her I just don't like being around her. I believe she jealousy because my relationship with my dad is stronger. I was raised by her and my relationship with my dad wasn't always perfect either because I resented him for a lot things when they divorced, but I moved on from them because it made me sick to hold the crap in.

Before anyone ask yes I'm in therapy because this and other things and this is another things she throws in my face. She'll make the comments "I need to talk to your therapist" and "I'm like why" her answer, I don't believe your telling her the who story". I told her "half a story ain't no story". I wanted all of my boys know they can come to me not just 2 out of 3.