vent about ex boyfriend - lots of typos and S/A mention

ok so like im a poly girl and atm im with 1 other person, we'll call him jo. then there's my ex from 3 weeks ago, we'll call him Avocado. My best friend, "New York", or NY, once came up to me and told me that my boyfriend at the time, Avocado, was flirting with her. i didn't care, because he flirts with everyone AND I'm poly. he isn't, but if he chose to also go down that path I wouldn't care because... why would i? that'd be kinda hypocritical yk. anyway, THEN she tells me, that she asked I'm if he was dating anyone, because she didn't know i was poly, and she didn't wanna ask him if he was dating me almost in like a trap type thingy. THEN HE SAYS HES NOT. idk if I'm like just a bad person but like when you're dating someone, no matter what type of relationship it is, (open, poly, mono, etc) YOU DONT LIE AND SAY YOU ARTENT DATING SOMOENE WHEN YOU ARE. NO MATER WHAT. RIGHT??? so I'm like hmmmmm thats weird. so i go up to him and ask him about it and he's like "yeah i flirt with like everyone" and I'm like "i know but like why'd you lie" and he's like "idk" and blah blah basically he didn't know if we were together or not WHICH IS SUCH BLUSHIT BECAUSE YES HE KNEW HE JUST GOT CAUGHT BEING BAD BECAUSE NEW YORK IS LIKE MY BEST FRIEND AND OF COURSE SHES GONNA TELL ME. ny is like such a good friend and was telling me everytime hed try and talk to her and everything like that. so recently, because he made me hella uncomfy and crossed my boundaries a shit ton and whatever, we broke up. THE DAY AFTER i found out he was dating someone new, through my friend, Pin. Pin, though, couldn't tell me who it was, because shes also his friend and he MADE HER PROMISE NOT TO TELL ME. like why would you do that unless you knew id be mad, YK. so i got suspicious. AS ONE DOES. so i was asking around, and nobody knew. I thought it was this girl, Mango. mango has a history with my relationships, she always somehow ends up being at least a part of the reason they end, including this relationship. someone even said it was her, and she was being extra bitchy to me that week. but the other day, he kept staring at me, and a ton of his close friends were telling me he still wanted me, and he does. so my dumbass friend macaroni goes up to him without asking and is like "you DONT have a chance with her. she hates you now, stay the fuck away" WHICH IS SUCH BLUSHIT BECAUSE AS MUCH AS I HATE HIM ID STILL GIVE HIM ANOTHER CHANCE. and to which he responds to her, without knowing she was gonna tell me, "no I'm dating someone" she asks who, and HE SAYS.... FUCKING NEW YORK. MY BEST FRIEND HAS ALSO BEEN HIDING IT FROM ME FOR 2 WEEKS NOW . EVEN WHILE WE WERE DATING, I SKIPPED THE SCHOOL DANCE AND PEOPLE SAID THEY SAW THEM MAKING OUT. I'm so upset. i don't know what to do. why would she do that? i get why he did it, he's just a bad person. but like wtf ny. I feel so hurt. even by Pin who knew all along and still thought not to tell me. even after i told her what he did to me and how he touched me without my permission, she still chose him over me and i don't even know what to do. nobody that I've mentioned other than macaroni know that i know. what do i do.?