WTF DO I DO?!

back story! : I was in a relationship for three years with someone who abused me, sexually and emotionallly. He cheated on me (atleast 7 times with different people that i know off). Well he had sex with this one girl, she tried convincing him to leave me and told eveeyone how "horrible" our relationship was. (i took care of his every need, we never fought and had sex atleast daily.) she had no idea who i was and single handedly tried to ruin my life. He dropped her and we made up. We conceived my son a few months later. Two years after i dropped that piece of shit when he neglected my son. I fell in love with my best friend, who was, at the time, dating guess who? that fucking bitch who tried to ruin my relationship. They finally broke up when he realized she was so full of herself she didnt give a shit about him. she went around and told people a bunch of shit "about" him.how he gave her a uti from not washing himself (hes straight terrified of being unwashed before sex, he stops to go wash it.) when she barely showers, you can smell her pussy just being around her 😷. Me and my best friend got together and over a year later now engaged ❤. Well, one of my best friends are pregnant and has a babyshower coming up (were the godparents) she just informed us his ex asked for an invite and them being in need of anything they can get, sent her one. i dont know what to do. my ex left me with ptsd and shes always triggered it. but i know if i ask my friend to uninvite her, that the girl will go off and bitch about it and shes friends with a close friend of ours we dont wanna lose and we know shed twist it around. but i cant miss the baby shower for our god baby!!! my SO asked if i wanted to stay home while he goes and theres no way im letting that bitch around my fiance without me there. any idea ladies????