baby shower stress ; Monster in law

RANT! Yesterday me and SO got into an argument because of his mom and my mom about the baby shower. How my mom is not putting enough of an effort to do more things in the baby shower and how my MIL she's already done the majority of the decorations and my mom should have called her to help with the decorations, I tried to explain to her my moms been occupied with other things like renovating our basement where me and my SO and baby will be living, my mom works as well and she's helped out when she can, also MIL has my moms number it wasn't hard for her to give her a call if my mom wasn't making the first move. That lady was not having it everytime I would say anything she would start up like how is it possible you see the mother of the father of the baby doing all the work your mom should be the one interested in doing the whole thing etc etc. At that point I'm starting to respond back to every little jab she's trying to make about my mom because HELL NA she not gunna talk about my momma like that and I will not stay quiet 🙂 .. At some point in the conversation my SO had left us to go pick up drinks for my baby shower from a family member who had bought them for us. To make things short me and my boyfriend are fighting by the end of the night because apparently I can never see where she's coming from and it's really not that I do know my mom could have been way more involved but I can't help but always stand up for my mom no matter what. So now me and SO are arguing because he's getting all this heat from his mom how I'm rude and talk back to her and how my mom is lazy and hasnt done anything. On top of everything she's like your mom didn't have to do the basement you guys aren't married, lol so condone your son being a part time dad and seeing his son on the weekends and some evenings that would be much better, this woman goes to church every Sunday but yet does not act like a good catholic woman. I'm 7 months pregnant so this stress is not okay to put on me, legit she should have just had her own baby shower and my mom her own like we were trying to do in the beginning but no me and SO wanted to combine our households #lessonlearned