my s/o is friends with, who i like to call, my “anti fp”.

this “anti fp” is someone who i have expressed discomfort with and dislike towards; they also have bpd and my s/o (and fp) is their fp as well. they have continuously crossed boundaries, and even flirted with my partner knowing full well that i was in the picture. i don’t want to put restrictions on my s/o’s life and friendships, but i have asked once before that they cut, or at the very least, limit contact with this person. they didn’t.

now, in any conversation, when they bring them up, and i am sent into a jealous loop. i get angry, i get anxious, i get sad. just... completely overwhelmed with all emotions. i hate hearing their name. i hate when my partner laughs at their jokes. i hate when my partner vents and rants to them. i hate when my partner asks them for validation. i hate it all... and i don’t wanna talk about it. it won’t get me anywhere. it’s so hard to admit. but i can’t show my anger, either. so i just shut down... completely.

i can’t keep doing this and i don’t know what else to do. how do i manage these emotions? how do i suck it up?