AITA for not telling my MIL about her surprise party?

I (f27) met my husband (m30) when I was 19 years old. I fell in love with him because of his sense of humour, his kindness and generosity. I also love how he always tries his best to see that everyone gets treated fairly. He has some flaws, but we all do and I think it’s worth it because the good definitely outweighs the bad. He’s also a very hard worker, a great cook and takes care of his physical and mental health. I’m very proud of him and very lucky to have him in my life. We have 3 girls together. He’s a great father. <br><br><br>Speaking of flaws, my MIL is definitely the worst of his flaws. He grew up with her being extremely critical of him. My husband didn’t have a lot growing up and so she was able to provide for him but she always made him feel like he would be nothing without her and that she was the only person who cared about him. I don’t know if this caused him to attract critical people in life or if he was too accustomed to it, but he was in a few relationships where he got treated poorly. <br><br><br>I broke that spell for him. I think I was the first person he’s ever met who treated him like he was perfect the way that he is. This made him and I both feel so good and I felt like his eyes just lit up all the time when we were together. He also made me feel like I was the only person in the world and he treated us really well. <br><br><br>My MIL hated me for this. I think I broke a spell for her too; a spell where she got to control him. She hated me because she thought that I was a gold digger and would take his money and run. But I never did that. I was independently wealthy when we met and I was even more wealthy than my husband. But it didn’t matter, she just didn’t like me for whatever reason. <br><br><br>For the last 8 years, she’s been very critical of me. I think she was relieved when we got married because she thought she’d still have access to him and control over him. But she didn’t. I asked him to set boundaries with her because he’d come home and be very sad and tired out. She was calling him and asking him questions about our marriage, our bedroom, where he worked and what he wore and if I was still in love with him. He was just fed up with her constantly prying into things that didn’t make sense. He was also tired of her ripping him a new one over random things. She called him FAT (he’s 6ft 190 lbs) and UGLY and said that I must be a gold digger because he’s not good looking enough to be with a woman like me. I guess she thought that if I was hot and he was ugly, that the only way he could get someone like me was to pay me. I medicine a lot for my career and he’s far more attractive than I am so it didn’t make sense. <br><br><br>I asked him to set boundaries with her but she was getting worse. So I asked if we could just cut her off completely. He said that he couldn’t do that because she was his mother. So I said we’d get therapy to work through this. He agreed we got therapy and the therapist said to establish boundaries and possibly cut her off if necessary. <br><br><br>He set boundaries with her. I guess she thought that if she couldn’t get to him, she’d get to me. She’d call me and ask me things and I’d just laugh and tell her that she was an adult and could figure it out herself. She’d get angry with me and call her son and get angry that he wasn’t taking her side. <br><br><br>These back and forth calls were very exhausting. We live in a different state, but she’d fly out and stay at a nearby hotel and tell him that he needed to help his mother. One day we had enough. We changed our numbers and didn’t give them out. <br><br><br>She’s not had access to us for 3 years. She’s still trying and she’s still calling. She’s getting really desperate now though and she’s trying to contact our friends and family and other people we know. She’s making up stories about how controlling I am to get sympathy. <br><br><br>A few weeks ago I got a text from a cousin of my husbands asking if we’d be coming to his MILs party. I texted back and said that we’d been cut off for 3 years and I didn’t know that anyone was throwing her a party. It was actually my husbands sister’s husband’s sister who was throwing the party. It was a surprise party. I texted back and I said that we weren’t invited but we’d be happy to come if they wanted us to come. They texted me back and they said that my MIL might get upset if we came. I told them that they needed to stop making excuses for her. If she was going to throw a tantrum that was on her. <br><br><br>They told me that they wouldn’t invite us to the party because they wanted her to have a happy birthday. I told them again that if she was going to ruin her own birthday by throwing a tantrum that that was her choice. They didn’t invite us. <br><br><br>I also didn’t give them notice that the surprise was ruined. I could have texted my MIL and told her the party was happening or called or emailed. I didn’t. I just let her turn up. <br><br><br>She threw the biggest tantrum ever. She screamed and she went through every emotion. She was angry and sad and happy and upset. I heard she spent the rest of the night crying and didn’t get any of her birthday presents. Actually, she got a few. The ones my husband had sent a few days before, but that was it. <br><br><br>Her family are now up my ass. They’re saying that I knew it was a surprise and I should have let them know that she knew. I feel like this is bullshit. She ruined every birthday we ever had and every Christmas too. She showed up to our wedding late because she thought that if she turned up at 4pm that everyone would focus on her. Our wedding started at 1pm. I just think she’s an ass and I don’t care that I ruined her birthday.