My 12 year old SD treats me like crap. She actually treats everyone who allows her to the same way. She is always right, and will argue with everyone. Her teacher, her doctor, her granparents, her friends. Everyone has to do what she wants or there is a scene, drama, fighting. Her friendships usually last a couple months tops, because she treats them the same way and they get sick of it. She takes things, lies, makes up awful stories. Her doctor told us when she was eight, that she is a pathological liar, when she hurts people by her actions or her words, and u explain why this is wrong, she says oh well. My fiance just gives in all the time. The thing is when, i am alone with her, she doesnt act like this. She tries, but i put her in her room and take away her ipad, and anything else she enjoys. She gets it. I wont put up with bad behavior. Her good behavior can last up to a week, but as soon as her dad gets home, she goes right back to her old habits. He also does not back me, when i say things. She will ask for something, he will say no over and over, like 20 times, raising his voice, then gives in. At this point, im almost 4 years into this. Lived with them for 2. Now I just bite my tongue, say nothing, if i dont have to talk to her im fine with that. She will talk back to me and totally ignore what i say and then 5 minutes later, ask me for a treat. PLease help. We are still living together, I truly love him, but the wedding has been postponed. Im 39, never married, he has been married twice already. All advice welcome.