Are we the asshole?

So a bit of backstory

My fiancé grew up living with his mother and stepfather. Well his stepfather use to abuse my fiancé and only stopped once my fiancé was able to throw him through a screen door. My fiancés stepfather would beat him for anything even if it wasn’t his fault. He use to get blamed for the things his half brother (biological son) would do. Well at 18 my fiancé moved out and went to live with his godmother in another state. For years he wanted to know his father but was held back because of all the shit his mom put in his head about his father. It wasn’t till he met me that he finally worked up the courage to contact his dad. He ended up meeting his biological dad and stepmother, who told my fiancé what actually happened between his mother and father.

Fast forward 3 years since we’ve been together and have a 3 month old child together. Since the very beginning of my pregnancy we’ve had to constantly remind his mother and stepdad that my fiancés father and stepmom would be in our sons life. That if they didn’t like that then oh well. Well his stepmother and godmother threw us a baby shower in New York where our friends and his family still live. Well his parents got pissy about that. But we literally invited them to the baby shower in Florida that my sister did for me but they made excuses about not going. Well earlier this month my fiancé father, stepmom, and half sister came to visit us and meet our son. My fiancé decided to tell a small white lie that he wasn’t feeling well to avoid conflict with his mother about his father being here. Well somehow she found out and now she’s mad at us. I just don’t get it it’s literally been 24 years and she still won’t let the past go. She’s the one that took my fiancé from his father and moved him around a bunch. She was there for my whole pregnancy but got pissy the two times we visited my family in Florida and his in New York. She was even there when I gave birth because I got induced and my mother wasn’t able to make it in time. Are we assholes for wanting to let our son meet his last set of grandparents and aunt without there being drama?