Upcoming BIL wedding dilemma

So I don’t care for my MIL. She has done MANY THINGS in the past to be downright disrespectful and gives half ass apologies when my husband won’t talk to her. Some things include: talking about me behind my back saying I control my husband, coming to my bridal shower drink and stealing items from the party, crying in the bathroom at my wedding, going behind my back to try to plan things I’ve asked her not to, lying to my husband saying I don’t allow her to see our daughter etc...

Well my BIL is getting married and his fiancé has asked me to be in the wedding! I’m so excited for them. The dilemma is, my MIL says mean things about the fiancé behind her back. She even tried to plot with my BILs ex to get him to cheat on the fiancé and break up! The fiancé doesn’t know any of this, but I do. She also has no information about the past between MIL and I. I don’t plan on saying anything to the fiancé. She has enough on her plate. I also feel that people need to make up their own mind about others and see their true colors on their own. However, she keeps inviting MIL to everything which means I have to tolerate her 🙄 fiancé has started to make comments about how “oh MIL just loves your baby so much” and “she just misses her since she doesn’t see her a lot” and basically let me know MIL feels “sad” that we don’t see her a lot. Like you HAVE NO IDEA what this woman really is! I’m kind of getting tired of the comments because I know she thinks she’s doing it out of love but she doesn’t know MIL is lying to her face. I’m trying to grin and bear it....

What do I do!?!?