is it wrong of me to not go to any family events if my fiancé's mom is there?

Is it wrong of me to refuse to go to any family events if my fiancé's mom is there? 

I've haven't her so many chances and she won't stop talking bad about me. I don't want to sound selfish but she's tried to break us up so many times. She told me to my face my moms a whore and sleeps around with everyone... she's told my fiancé that I'm just using him for a easy way out, told him to not adopt my daughter that I'm only marrying him so he will have to pay child support(makes no sense)  told him that I sleep around and that I'm disrespectful to her for not trying to prove her wrong and be her friend after everything she has said. She's said SO SO much stuff , the list can go on. She always tries to make him feel guilty for marrying me trying to talk him out of it.. I've never said anything to her.. in fact I've met her one time.. and some and her talked for like 2 hours straight and we were both super nice to eachother but as soon as I left she started talking about me for no reason.. my fiancé is in the military and is visiting in April and wants me to go to dinner with him and his mom but I'm just not comfortable with it. I feel like she will talk bad about my daughter,she's 15 months. Or something else.