Step Daughter problems (need advise)

My wife has been an enabler for her for years and my stepdaughter knows that all she needs to do is start her drama and my wife will come running. me and my wife have had several arguments regarding this and i have told her point blank that her own daughter continues to stick a knife in her despite all of her kindness and help she has offered to her daughter.i finally told my wife that she needs to keep me out of her daily issues. I do not need to hear it. I follow what's going on in other ways and know that my step daughter is still the same.with the lies, stories and bullshit excuses. What my wife does not realize as that I have access to her court proceedings because I also signed the papers for guardianship of her other daughter so i am allowed to see her files.