My parents have been divorced for as long as I can remember. I believe I was six at the time, in fact. Both of my parents have new partners. My mother has a boyfriend, who I get on really well with. They have been together four years and he moved in a year ago. It is nice as with my mum, her boyfriend, my sister and me, it feels like a proper family again.

My father's girlfriend, who he has been dating on and off for six years, moved in last November. She has since been controlling and ruining our lives. Firstly the move in was quick, as my father and her had only been properly back together for a little while and we hardly saw her. Neither me nor my sister were comfortable to start with. Since then her and my father have been arguing constantly. She complains that he gives us too much attention, and she always comes second to us. She also complains because he takes us to activities at the weekend, as she feels he should be at home with her. However we always do these activities (things such as volleyball) so, why should we change them.
Have to stop for her. If he does not change something for her (such as he once shortened a holiday with us to see her) she will then have a fit and walk out. This happens once a month, maybe twice. These fits are really over the top, and just downright crazy.
She also says horrible things about my mum to us, which is horrible and unfair. She says when she does this, she is just trying to get us to realise the truth about our mother. She also criticises my sister and me, saying we are too spoilt and don't accept her. She says we don't really care about her father, and that she is the only one who would care if he lived or dies.

She is making me not want to be at my father's house, and even not want to be around him as she is there. I feel she is ruining my relationship with him. I feel I have no respect for him anymore.

What do I do?

You need to sit down and talk to your father about this.