I don't know where the lines should be drawn with my boyfriend's ex

I want us all to get along, but feel that I am not being respected. Of course I do have some insecurities because he was with his ex for 8 years. He wants to see his step daughter and ex makes it so he has to go there to see her, but she doesn't want me around. She has a boyfriend, but mine fixes their vehicles, goes over once a week and hangs out with the ex and does family things with her. Since he works nights, I only see him parts of Friday-Sunday and we live together. He won't let me use his phone when I forgot mine, says his ex used to mess with it. I don't think he's cheating, but he will lie about what time he actually left her place to come home or about going over early to be with them. I feel like the other woman. She has tried to mess with holiday plans by restricting when he can see the child. He only dated once person before her, so this could be why. I don't feel he has let go enough. He is a wonderful boyfriend other than this.