MIL drama

Sorry in advance for the long post but I really need to rant! For a little background my partner is 24 has a son from a previous relationship. I have always felt like my MIL has always thought that I am a second choice. My partner had a graduation last year (before having our little) and he had limited tickets to go, he obviously had his family go but gave his last ticket to his baby mama because his mother said she deserved it more than I did since she picked up his slack in watching their child from needing to graduate the academy. I was obviously hurt by this not only by my partner but my MIL too, I try to never hold grudges but this one just seems to stick no matter how much I try to talk it through. My MIL came over to see my baby a few days after our child was born and upon walking into our freshly moved in house that wasn’t totally ready yet, cause we were not expecting baby for another 4 weeks she immediately says “wow you guys really need to clean up in here.” As if that wasn’t bad enough she goes into the kids room and looks at me and says that she HAS to redo it because she “doesn’t like it” and it’s “not symmetrical” My partner redid the room without me when I was taking a nap to satisfy his mother and it still was not good enough for her. Fast forward to about a little less than a month of having a new baby- she expects us to bring him to her and will never come over. Which after the last time she came over and just complained how our house was set up I was okay with it. She expects to see him every week and when she sees the baby she won’t give him back even after being asked by either one of us and says no because she never gets to see the baby. Yet before having a baby she never cared to see me at all. This has caused some tension between me and my partner lately because I don’t want to go to his Mothers house as much because i don’t feel respected or listened to. He asks me why I don’t like his mom and i’ve told him that is ABSOLUTELY not the case, I do get annoyed because of lack of boundaries with her but I have tried everything to get some sort of boundaries. Anyone have ANY advice or any similar situations? It would be so much appreciated