Toxic mom. Wedding planning. Help!

So my mother and I have always had a wishy washy relationship. Well I guess I should say that’s her relationship with everyone in my family. My fiancé and his family are aware of my battles with her. In February our family home burnt down. We all had our suspicions she did it but we never wanted to believe it. Well she admitted it to me about 2 months later. I told my family but it’s the same as it’s always been, “shes mentally sick, forgive her”.. and so I’ve done my best. Physical and mental abuse are not shy in our relationship. I’ve distanced myself from her since she admitted the truth.

Well I got engaged in May! I have been so happy. My fiancé and I have been together for right at 5 years. He is the love of my life and very understanding about all my family issues. But then my mother got married 3 days after I got engaged, not a traditional wedding. Not to her boyfriend, to someone she’d never even officially dated. She just decided over night she wanted to marry an alcoholic. Nevertheless, I’m just giving a little bit of back story..

My future mother in law went wedding dress shopping with me, and I found my dress! I was over the moon and texted and told everyone!

But then I had to decided on whether or not I tell my mom.. would she yell? Go crazy? There was no telling. But I texted her anyway because she is still my mom. It’s been 4 days and she still hasn’t said anything. I don’t know whether to just distance myself from her while we plan the wedding and just pray the day if she doesn’t cause a scene.. I have no clue. I need advice. Have y’all had a toxic mother? How did you handle wedding planning/the wedding in general?.. 😔