AITA for asking my mom to "quit bringing drama into my life" and that I want "nothing more to do with her boyfriend or his family"?

Fiancé and I are getting married this year and my mom, since I'd clarified to her that her boyfriend's daughter can't come (she's known since last summer that this was planned to be a very small wedding with immediate family only \[siblings, parents, and grandparents\]) has been acting like a basket case.

Her boyfriend is claiming that if his daughter can't come, then he won't go to the wedding. So my mom has been telling me several times how stressed she is by this and keeps requesting that we reconsider and allow her boyfriend's daughter to attend, to which I keep telling her "no".

I finally blew up and told her "That's it, I'm done." I ranted that her boyfriend has no right to even attend this wedding anyway given how he's spewed lies about my fiancé "being controlling", which is rich because he himself is a controlling narcissist when it comes to my mom. Further, he makes my fiancé and I uncomfortable whenever we have to be around him.

She has now been consistently bringing drama to my phone line for the past week, claiming that if her boyfriend isn't going to be there, then she won't stick around at the wedding very long either to celebrate. And then she also threw it in my face that my maternal grandpa likely won't attend either since he "doesn't have a ride" and "can't drive himself" and that "if my maternal aunt were invited, she would've driven him to the wedding." My mom was pretty upset when she was told last year that we were having a micro wedding.

I told her if she's going to keep being dramatic about this, then maybe she "shouldn't come to the wedding either, as much as that would hurt me". I also told her "You realize your boyfriend has step kids and more than just his single biological daughter, right? If this is how he treats his step kids, then I want no part of him in my life. I'm done with him being whiny and always stirring the pot. I don't want him in my life anymore. He can never just leave things alone. He always needs things done HIS way, and its upsetting how you always put him and his feelings above your kids, just like you're doing now. You'd rather put your kids in stressful situations to appease yours and your boyfriends comfort. He's done things to me in the past that he's STILL never apologized for or even acknowledged, and by now, it's too late. He's ruined my 20s. My only hope is that my 30s will be off limits from him."

"Not to mention, since you've been dating him, you've turned into someone I do not recognize. You've changed your appearance and personality completely and you cry in public and cause scenes for your kids all the time when you NEVER used to do that. I'm done with all of this. Please stop. And go to therapy. I love you, but you make life so hard for me lately. I miss my mom, and I miss being happy. Please just let me be happy. I can't deal with the drama anymore."

She now hasn't talked to me for several days. AITA?

For what it's worth, we're paying for this wedding by ourselves with no assistance.