Okay, I am so lost and unsure what to do, I have been with my boyfriend for 2yrs now, But we have known each other a very long time. My B/F has a 9 year old daughter and I have known her since she was a 1yr old and have been in her life (so its not like she dont know me).  Me and her can't seem to get along since me and her dad got together. * I have a son from another man, and me and my b/f are expecting here soon *

Any way's... We get her once aweek and sometimes at most 3 times a week. She shares a room with my son which is about to be 6yrs old. So she has a space for her things, and its not like she don't have any thing etc.
But any time that I ask any thing of her, she speaks to me very rude, and tries to just get in a fight about every thing. Of course she don't do this with her daddy around.  I am lost and unsure what to do because I have spoken to her dad and this has been going on now for awhile and just seem's to get worse. I have been just letting it roll off but I have had enough, Dad say's that, "that is just how she is" and that "I am sorry but I am going to spoil my little girl"
that he don't get her all the time, he dont want to ride her on cleaning up her mess etc. " I am sorry but regardless if she is there one night or two and play's with her toys and does what ever with her clothes and they end up all over the room and on my son's bed, I would think that she should pick up her things" But I guess I am wrong about that.

She is the little girl that uses the daddy trick and she has him wrapped around her little pinkie and I just can't take it any more.

I am not asking him to make a choice of me or her. But I dont feel as if I am a adult in my own home when she is there.

I have to walk on eggshell's because if I do something to her ask her any thing . The water works turn on etc.

Now also I have a issue with her putting her hand's on my son. Dont get me wrong my son is not perfect and most the time a brat, but When ever she is over and they cant get along she will try to hurt him in some way.

But again daddy back's her up and say's that  maybe my son did something to her.

I am just at a lost cause and don't know what to do. He say's that I should change and not ask much of her? I ask the same of my son as her when she is there. He also states that maybe she just has a grude .

I love him, But I am starting to think that we are just not going to work out because his daughter wan't him all to her self, and well we are having a baby together, and that worries me.

I am considering leaving him because I can't deal with it any more and sit by and let her run my house and her dad like she does.

Please Help me with a stubborn, demanding very very spoiled girl, and a Dad that just want's to do every thing for her cause he think's he has to make up for something.