I am a future step parent, my boyfriend and I are in the stages of talking about marriage and buying a home. I've been with my boyfriend for 3.5 years and he has one Daughter who is 18. I've been around and been in their lives since she was 14.5. The bio-mom is not in the picture at all whatsoever and has not tried to create a connection with her daughter since birth. According to him, he prefers it that way because she is unstable.

Background

When I first met his daughter, in my heart I was excited and nervous. He'd ask me how I felt about dating with kids and I assured him I am great with kids and was looking forward to getting to know her. I moved in with my boyfriend pretty early, he wanted me to. I had my own place not too far but we felt like it was the right step. Initially, his daughter and I had a great relationship, I'd buy her things, we'd go places, take cute selfies, I'd include her in my boyfriend and I's movie time, etc. I had a genuine love and concern for her. I also found out early on that she had some behavioral issues, and she was having to go to court for attacking a classmate with an exacto knife. "He's a bully!" she said. As time went on, I noticed she'd get in trouble ALOT. Almost every day, the school would call about her behavior. Also, at home she would get into it with her father a lot about her grades and schoolwork, not cleaning up, not taking his things, etc. but never any issues with me. I was the peacemaker and tried to find solutions - I chalked it up to teenage angst.   At this time, she was diagnosed with Autism and Intellectual Disability along with emotional disturbances. About a year after I moved in, we all moved because she was able to get great services through another school district and was enrolled in a school designed for kids with severe mental illness.

When we moved, her dad had to work more and she and I would be home together more often. The more I had to enforce rules, her true colors started to show. Her attitude to everyone is completely nasty, she will act sweet but the second you have to tell her what to do and she does not want to do it - watch out! In addition, she would blatantly lie to her school therapist about bizarre events that did not take place, she professed her love for a certain school shooter to school authorities and us, she began to steal from me, she would go into our bedroom and steal from the both of us, she stinks and does not have good hygiene, she doesn't clean up after herself, she would pee on herself constantly - even in public (literally standing in an elevator or store and would pee), she would steal food out of the kitchen at ALL hours of the day, she couldn't be trusted to be alone, she got into arguments with her father and threatened to stab him, she had been put on several 72 hours holds, etc. She started to say things to me like I have no place with my boyfriend and she is mean to me now because I remind her of his ex-girlfriend. I've talked to my boyfriend about this and he confronted her about it, but it doesn't do anything to change her perspective. She has hit me (and I hit her back and made her think twice about doing that ever again!), called me out of my name, tried to put her father and I against each other by telling lies, had CPS called to our house, lied to her school authorities about being abused in the home, etc. She is a literal nightmare and my boyfriend is just so ill-equipped - he isn't consistent with reprimanding her. He will yell at her or talk about it and that's it. He claims we've taken everything from her and there isn't anything to take, yet, she gets her cell phone. (Oh i forgot, with his logic she's 18 now smh) When she and I get into because of her disrespectful mouth, he gets mad at me for putting her in her place! He says that I am an adult and she is special so I need to figure out how to get along with her. He has also said things like this in front of her. It's gotten so bad that if I say one thing to her, she feels empowered to go "tell on me." 

Well this last time, she told on me and I let them both have it. I moved his daughters shoes because it was early morning and I tripped and almost fell over them. She heard me moving them and came into the living room and I told her why I moved them. I placed them near her table in the living room so she could grab them easily before she left for school. She walked out and came back and said "I don't know why you keep touching my stuff." I told her to shut up and just get out. I felt the anger rising in me because this is a consistent pattern. She said " I'm going to go tell my dad" I told her go ahead, please go.  So she's telling her dad and I got pissed I went in the room and heard her say I'm so rude to her and I told her I speak to you how you speak to me. and I told him what happened so he gently tries to explain why he moved her stuff. I was enraged. I interrupted him and said "you don't need to explain anything to her, I've already told her why her things were moved - stop pacifying her." I walked out. He got mad at that and came to my office and told me that basically he can't do anything about her behavior. (We've literally tried everything) And that I shouldn't talk down on his parenting skills because he's doing the best he can. And basically to solve it all I should just move out because this issue with his daughter is an ongoing thing and he's tired of dealing with it. I told him I'd move out.

Apparently, the move out is also facilitating a break up because he doesn't understand that I can't fix a broken situation that I did not start. I've done everything to help this girl including discipline (from both adults), labeling things, following the therapist suggestions, etc. Nothing works, even her therapists and doctors are floored. She's literally a lost cause. My boyfriend is already making it so that she will spend the rest of our lives with us and I DO NOT want that. Should I just move out and lose my boyfriend who I love dearly? Or stay in a situation where he puts his daughter and her needs first?