Fighting With My Wife

Hi Coaches , my wife and I combine our family 12 years ago. We went through the teen years with three girls and 1 boy. Now they are all trying to find their way in their early twenties. We have always fought over each other kids. I have decided for myself that her kids are mine as well and to love them unconditionally. It wasn’t easy and I wish I had of do it far earlier for their sake and mine, but I truly feel at peace with our relationships. My wife on the other hand is in my opinion not thinking of my kids as her own . She is always asking me to tell them to do something. Often I don’t even agree with her what she is asking. I find her to be very negative towards my youngest daughter. I know she isn’t easy to live with but it doesn’t make it easier to have my wife constantly complain about her. On top of that my wife gets upset when I do chose my daughters side . She feels I should always side with her and she has a lot of expectations. It’s exhausting . I know I’m being judgemental . I can see my thoughts are creating my feeling , but I just can’t seem to change them. Please give me guidance .