My husbands ex girlfriend is harassing me! Any advice??

My husband and I are separated at the moment, pending divorce. We have been married 7yrs. We began living separately in May. We have 2 boys together. He cheated on me twice with his ex (once before the marriage, once after) and both times she exposed him and the cheating to me via Twitter. He continued to contact her and vice versa off and on throughout our entire 7yrs of marriage.

Finally I decided things weren’t changing and it would be best for me to leave. He now has a new girlfriend that the same ex has been feuding with. He’s blocked his ex from contacting him (I guess) so she texts him on a group text thread that I started almost a year ago. She claims she’s doing it to ensure that he gets the message. I’ve asked him to handle the situation so that she can leave me alone but he just ignores me and tells me to ignore her.

Am I wrong for responding to someone that’s continuously contacting me over his mess? Something that I am not involved in? I’ve dealt with it for 7yrs I just want to be free of the drama. Any advice would be greatly appreciated.