OMG I am having the same problem ! Except worse ! I had a 7th grade boy and he had a 2nd grade girl when we got together. Her mom is totally out of the picture. Anyway,come to find out she has ADD,visual perceptual motor delays etc. I had to get her in Special Ed. classes and work with an OT at school. She did 1st grade 2x. with Dad and G-ma. His family was furious. I have never got along with her and believe me I even tried a psychologist ! She just gets worse every year ! She is mean,sneaky,talks back,never listens,gives me nasty looks,lies and causes major problems in our relationship too ! I feel for you because I really do know what you are going through ! My friends are mostly teachers and they even shake their heads at this one ! Dad is always at work. He is clueless ! I even caught her peeling off the wood on my antique furniture of my deceased grandmother ! We have tried EVERYTHING ! I finally put her in with a psychiatrist ! Last resort but had to ! I should have done this earlier ! I just started and it is a little $$$ but I had to save our marriage ! So,if you have tried everything else I would suggest you do that ! They can really get to the root of her problems. If you don't do something your other kids will copy her. You might even end up in Divorce Court ! That is probably where she wants you so she can think she will have Daddy all to herself ! Good luck !! I bet you are sorry you asked ! lol