MIL issues

So let me start off by saying I really dislike my MIL why because shes a two face. My issue with her is she constantly feels the need to be bringing up his ex. In front of me at family gatherings . At first I was like ok I'll let this one slide then 2or3 other occasions same thing. I told my husband either you put a stop to it or I will. He talked to her she said she'd stop. I stop going around and talking to her because she's a two face. So the other day my husband stop by at there house. He walks in and first thing she says guess who I talked to and bla bla. Well the ex. Then she goes on and ask "do you miss her at all" that pissed me off because wtf is she asking that. I'm guessing if he did he would be with her. So then my husband starts telling me that they all have communication with her again and there always mentioning her to him when hes told her shes the past. What should we do? hes talk to her and I want to talk to her but one of his aunts told me not to talk to her that she will because she can take it the wrong way if I do. I'm so sick of it and everyone bringing her up.i completely cut all them off but my husband cant keep anything to himself he says he tells me everything because he doesnt want to keep anything