Help with step mother?

Step mother has been bothering me. She's always been obsessed with being their mom since long before she broke up my marriage and finally married my ex. I am the custodial parent, but she constantly berates me in front of my children, on the web and with relatives that buy her act. She ball busts my ex into harring me with the legal system and she's trying to get him to go after custody. They are both unfit parents and I want this emotional torture to stop. The father never gave a care for his kids until she nagged him into it and he just wants to get them for her to have. He complains about paying cs, he pesters me for doentation of everything so that he can try to use against me. He won't talk about parenting with me, when they are at his house she's the boss. Any advise?