How do you address problems with your bfs mom?

How to you handle/confront issues with your bfs mom? Do you go to your bf and have him handle it or go to his mom directly? I’ve been told that my bfs mom has recently said some pretty nasty things about me and I’ve been trying to figure out how to address it because I don’t want to just keep my mouth shut. This is not the first time I’ve heard of her talking bad about me so I want to just squash it and call her out this time, but idk how to go about it. My bf is pretty short tempered, I’ve never felt totally comfortable talking to him about things that bother me because he blows everything wayy out of proportion and turns everything into a HUGE deal. Hes also very close with his mom so going to him first will probably go one of 2 ways. He will either flip out and make it a massive deal between everyone involved and make it messier than it has to be, OR he will just brush it off or take up for his mom. I could just go to his mom directly without going to my bf but she’s either going to argue with me or she’s also gonna blow it out of proportion and run to my bf to try and get him on “her side” and make it look like I’m just attacking her then they’re both gonna be mad at me. Idk how going to them both would go because again they’re really close so there’s no telling how that would go. I don’t wanna just leave it alone though because I’m so tired of her going around talking about me I feel like she does it because I never call her out I just don’t know how to address anything without it causing a bigger issue than it’s really worth.🤦‍♀️🤦‍♀️ we’re all grown adults so I want to address it civilly if possible, I don’t want to start an argument with nobody I just want to clear it up with her and firmly let her know I’m tired of the gossip all the time and it needs to stop.