Good afternoon,
I am married to a beautiful soul, a man who has a heart made of gold. We have been in a distance relationship for two years before getting  married and moving in. He has two daughters, the oldest is 12 years old (non-biological), and the youngest is 8 years (biological). The oldest daughter has no manners, dirty, and cause plenty of problems...
When i first started living with them, father found out that she wrote terrible things about him in her dairy like: "old man, he is not even my dad"
" i feel so sorry for my sister that she has to stand a father like him forever"
"I am going to send everyone that lives in this house to jail, i am a woman and a minor so the police will believe whatever i say"
"He is even crazier than my biological  father".....
The last thing that she did is that she sent her mom screenshots of her dad's conversations with his ex's family memebers telling her mom look what they are saying about you.... 
When my husband  found what she wrote about him the first time, he spoke to her and explained to her how he met her mom and that she was so little and that he decided  to adopt her and take care of her when her sister was born.... but  when he found about the screenshots, he punished her without tv, ipad..... i tried to convince  him that maybe he should do things differently and that he should return that girl to her mom's house to live there forever because she is acting like a spoiled brat, doesn't  respect  anyone, and cause tons of troubles, she is unhappy most of the time, makes faces all the time. He is filing a custody case, he wants them to stay with us 24/24 and 7/7. To be honest, i don't  want the oldest one to live  with us as she is so dangerous, i don't  trust her.... i told him that all the problems are following  you because of her, she is the source of problems in the house, i think he did enough for her and now it is time to return her to her mom's house (of course, in a legal way), i told him everything but it seems that he is not ready to give up on her. I sometimes think of leaving everything behind and moving forward. I am drowning in problems that are not even mine. Of course, i don't have the right to talk about kids nor talk about them for the moment. It doesn't make sense for me that he is taking care and charge of his ex's daughter while his ex is milking money out of him and treating him so bad... please advice me, should i be more patient? Do you think  that the girl will change one day or another? I am not happy nor motivated in this relationship