Frustrated

I don't like to post negative things, and I try not to. But I need to know something. Why is it that kids think it's ok to listen to one parent but not the other? Or they know they can't get away with treating one bad, but try to with the other? These are the problems I'm having with Alex right now. She listens to John and fully respects him and his word. Me on the other hand... not so much. It's the same with her real mom though. Alex doesn't treat her mom good at all, but for some reason, Jessica lets her get away with it. But then she tries to pull that same behaviour with me only I don't let her get away with it. That only makes it worse though. It's like it becomes more of a challenge to her and she just tries harder to win. It's a constant head butt. John has tried to make her stop, I've tried to make her stop, but it's a losing battle. She doesn't think she needs to. We've sat down as a family and talked about what she thinks I do to make her want to treat me this way. What comes out is she resents me for making her do chores, giving her guidelines, and overall making her have common rules. Even though most were in place before I even came into the picture. Now she has someone to blame (she wouldn't dare blame John because she knows how much trouble she'd be in if she treated him like that). I don't mean to unload my problems on everyone. To be honest I don't even think of people reading this. It's more like a therapeutic outlet for me since I don't really have anyone to talk to about this stuff. John just gets mad when I bring it up because he doesn't like dealing with the problems either. I get too much built up and I just have to release. To those who have read this, I apologize. But I do feel better.