Brief backstory - I have sole custody of a 4yo girl, my SO has random visitation of a 3 yo girl. We lived together for a year, for about 8 months of that we had his daughter every other weekend. Because of the following issues (and some other things), we split up in November. He moved out. He decided he wanted to try to fix things, I told him that I thought there were some major issues that could not be fixed. Here it is March and we are "back together", but not living together full time yet. My daughter thinks of him as "daddy".
His daughter and I got along well for a while, she was even tempered (as much as a little kid can be), got along fairly well with my daughter, etc. Then around June? I started noticing her getting VERY angry all of the time. We had always had bedtime issues that were NOT helped by my SO's inability to do anything that might "upset" her, but her behavior really was changing. She progressively became more and more violent. At first it seemed to be a jealousy type of thing - she would physically lash out at me or my daughter if we went near SO. Then it became that she would actually track me down in the other room just to kick me, or scratch me, etc. We ended up having to send my daughter to my parents on SD's visitation weekends because she was winding up with so many bites, cuts, bruises, etc from SD. And my DD is a BIG girl - 90th percentile. His DD is in the 20th. So imagine the size difference, and my DD was winding up bleeding half the time.
She started biting my SO, hitting him, screaming for 2 hours straight if you told her "no" - and it didn't matter what tone you used, we experimented with that one. I tried to go out of my way to include her, reassure her that I loved her, etc. She would literally spit in my face if I knelt down to talk to her.
So that was when I really started getting mad at SO for not doing SOMETHING about it. His idea of discipline was to pick her up, toss her on her bed. She would jump up 2 seconds later and come back out in the other room. End of "punishment". He finds NO problem with how he handles her, does not let ME discipline her at ALL.
I have tried to explain to him that I will not be able to have her in my home every other weekend while she is being violent. He says I should listen to myself talk, that "violent" is ridiculous, and I shouldn't "badmouth" his daughter. I am not badmouthing her. She is violent. Without provocation. It is unsafe for my daughter to be around her, and I spend 90% of her visits in tears.
I love him, he loves me - but we CANNOT get around this issue. I have told him I will not marry him/move him back in until it is resolved.
What can we do? I'm angry at him, not her, but just the thought of her being here makes my blood pressure rise and I feel like I don't even want to be in the same room with her.
Any suggestions, etc are really appreciated. I don't think she should have to be upset for an entire weekend, and I don't think me or my daughter should have to be either.