just learned my ex is in a poly thing with people we never even played with, why does this sting

split 14 months ago. amicable. moved on with my life, dating again, doing well. yesterday a mutual told me my ex has been living in a poly triad for like 6 months with two people who weren't in our old play circle, brand new connections she made after we ended. and reader... it stung. like really stung. why??? we were swingers for years, i watched her be with other people loads, never bothered me. but now finding out she built an actual nested poly thing without me feels like a punch in the chest. is it the structure? the commitment? the fact that she's clearly fine and i thought i was further along than her... what is wrong with me