Hi welcome to PC. I'm sorry that your upset. I think that it's good that your bf tries to get along with his ex. He doesn't need to like her, but for his child sake he needs to get along with her. I would also say that you and the ex have issues with each other. If you don't want you and your bf to argue over this, the best thing to do is ignore her. The ex is doing this because she knows that this will get to you, and your feeding into it. His ex is probably thinking in her mind that she keeps on starting trouble than sooner or later the two of you will break up, and she will get another chance. Does your bf hang with her? If he's not then you probably have nothing to worry about. If you can't trust him then maybe he's not the one for you.