finally blew up at my MIL

idk why i'm posting this. i guess cuz i'm still just extremely frustrated and need to get it out but don't like gossiping with people who actually know me and the people involved.

my mil has always been emotional and makes everything about her. the newest one happened today. my son has been taking steps for about a week. my mil lives in another city so my husband told her over the phone. I know he did because i was there and she asked for a video and we said we had been trying to get one. today I finally caught him so I posted the video to facebook (as we all do lol). suddenly, 20 minutes later she's texting my husband flipping out saying how dare you not tell me he's walking, I had to find out on facebook like a "regular person" 🙄 and saying that she's clearly not part of our family (wtf) and our son only has one grandma and that's my mom cuz she doesn't feel like his grandma. again, we had already told her but she takes so many pain meds (prescribed, she's not an addict) and doesn't ever remember things. my husband tried explaining but she would not believe us and continued to flip out and yell at my husband over the phone while i listened, watching our happy moment that we finally got to share with all our friends and family go down the drain because of her. now, she's done things like this a lot and every single time i've stayed out of it, even when she has said things about me personally. but today i couldn't take it and the reason why i couldn't is I did not even get to see his first steps. I just went back to work and was already really down about it and of course my first day back is the day he took his first steps. i'm his mother and I missed out on a big milestone but I tried not to let it get me down and here she was crying and whining about a facebook video, making my husband feel like shit for something that should not have been a big deal. so I lost it and finally told her how i felt. I wasn't disrespectful, but I definitely didn't hold back. after five years I just couldn't take it anymore. she has taken the joy out of so many moments because she had something to complain about and has started so many fights with my husband over nothing. my husband hardly ever wants to visit her anymore because it always ends up in a fight whether its because we don't stay long enough (even though she knows my husband works) or because we can't come the exact days she wants us to even though she gives us like two days notice despite us telling her over and over again that we need at least two weeks so we can request days off, or just other things like that. the entire family knows that she is out of control but they just aren't the kind of people to tell someone when they're doing something wrong, they just bottle it up. well i finally had enough and had to speak up. of course t was a text message because she had hung up on my husband and was ignoring his calls (which is what i think pushed me over and made me get involved because that just made the whole thing even more ridiculous) and so after a few messages she stopped responding. i didn't get it all out. idk if that's good or bad but it is what it is. if this ruins our relationship, which was already strained (and of course for no other reason than crazy things she made up in her head that had nothing to do with her and i have always been so kind to her even when she would say hurtful things about me not knowing i'm listening) then so be it. I just couldn't sit and let my husband take the abuse anymore. idk what it is about moms of boys but i'm going to do everything in my power to not be like this. and if i start to, i hope my husband will remember these moments and talk some sense into me unlike anyone in her family has done