Guys fucking help.. (Friendgroup drama/crisis)

So there's a person in my friend group who keeps asking and bating the idea of my, my boyfriend ,them and another one of my friends getting into a poly relationship, for context, I personally have trauma with poly and all of my friends know this, but this friend (we'll call them M) keeps asking and bating the idea of it happening. Today M told one of my close friends to ask my boyfriend what his ideas on poly is, I'm about to be fucking done, I already lost a friend to something like this and you know what? I'm honestly ready to lose another because this is making me so uncomfortable, my mum even told me that if I have anymore school drama brought up to her then I will be homeschooled, I'm not about to have that happen, fuck that.