MIL from HELL

My fiancé and I got together when we were 18 years old. We are now 20 with a two month old. Up until about 2 weeks ago we had been living with my fiancé’s parents (ever since we first got together). First and foremost I’ll give you some insight into how my mother in law acts (let’s call her sally) she Is a spoilt ass brat. She throws tantrums when she doesn’t get her way, she acts as if her shit don’t stink, and she thinks that her opinion trumps everyone else’s. She is an all around TOXIC human being. I am going to preface this huge argument with previous argument we had when I was about 6 months pregnant. As I was nearing the end of my pregnancy my grandpa offered to sell us his mobile home for 8,000 dollars. He was going to allow us to pay 400 dollars monthly to him until we had paid it off. This particular mobile home is situated in a mobile home park next to my mother. My fiancé and I were very excited about the offer because WHERE in the hell can you rent a 2 bedroom 2 bath with walk in closets for 400$ a month??!? So anywho we are super excited and we decide to tell sally that we will soon be moving out to be independent because baby will soon be here. This woman becomes LIVID. She starts cussing calling mobile homes and trailer parks trashy, and that my child would end up being on drugs if we moved there etc etc. mind you I have lived the better part of my life in a mobile home and sally essentially called my family and I TRASH. I packed my shit up after that and spent the remaining months at my mothers home. So September rolls around and I end up having baby a month earlier, we hadn’t saved up enough cash to be able to move into my grandpas trailer because as I said baby came early. So this vile woman being a snake in the grass, offers to fix up my fiancé’s room and offers to get us a storage unit so that we could store our house stuff until we got ready to move out. So there I was, a new mommy in a house where I felt unwelcome. At first sally was not overbearing with baby. Then little by little she would sneak and give him baths before I could. Then she would automatically change the clothes that I had just put on him. She would negate every comment I made about him. She quite literally became obsessed with my baby. On top of her being a complete obsessed psycho, my fiancé’s two younger brothers live in the house as well. And they do not give 2 shits about being loud and waking baby. The house is chaotic, sally is crazy, and I feel unwelcome. So I express all this to my fiancé and he agrees that it is time to get our own place. We are 20 with a baby of our own. The night before the huge fight ensued my MIL & FIL sat my fiancé down and asked him why he had been acting different. He expressed how his brothers didn’t behave and they had no consequences to their actions, he explained how sally had been trying to parent our child, and he explained how he was tired of being told that this is not his house. So that night we decided to pack our stuff up and move in with my mother. My mother is moving in a few weeks to a house she bought and she is going to let us rent the trailer from her! The next day we started moving our stuff. Sally is LIVID. She begins cussing and saying that she gives baby one month before he is sick in that disgusting trailer. She begins calling my fiancé a piece of shit freeloader. And then she starts on me. She told me I ruined my fiancé’s life as soon as I walked into it. She told my fiancé I was lazy and that he would have to do everything around the house,work, and take care of baby. She told my fiancé that he fucked up because he got me pregnant and he dropped out of college and she basically blamed everything on me. She basically called my child a mistake. I am so dumbfounded. The venom she spit had my fiancé is such agonizing tears. He cried for days afterwards. She screamed and cussed and threw dirt on our names the whole time we were trying to simply get our stuff and move out in hopes to be more independent. Now 2 weeks later she says she is sorry and that she wishes she had never said any of that. But I do not believe the crazy bitch. My fiancé has forgiven her but I can’t bring myself to. I know this post was long but I don’t want my baby around such a toxic person especially if they think me so awful. Is it wrong to keep my child away from my MIL????? Please all opinions are welcomed I am so tore up.