I will preface this with the fact that that this person never specifically said "poly" but I deem "open relationship" and poly to be one in the same.
I wasn't looking for anything serious at the time, and was pretty much just looking for a hookup or someone i could keep as a booty call and found someone on Tinder. We hit it off and met a couple times before hooking up and he made it very clear we aren't in a relationship. That's fine with me.
We acted like a couple but weren't one. I guess it's what he wanted out of the relationship? I wasn't fussed as I was still getting some. The relationship we had "open friends with benefits"/"open relationship without the romance" scenario (making his later actions even more :autism

was a mutual agreement. He was telling me that I could see other people... Even though I was still technically single. Makes sense, even though I didn't really need his "permission" as we weren't exclusive/in a relationship.
Later on in the year there was something going on near him and he asked if I could join him and his friends. I stayed at his house the night before and was supposed to stay for the weekend. Shit hit the fan on the first day of this event. All day, he's telling people "we're not together in that sense" when they commented on "you guys are a cute couple" (cringe), which is true, so it wasn’t a big deal. At this event there was a lot of drinking. AKA we took a shit ton of beer and stuff to this event to share between us and his friends to get shitfaced. I get horrendously drunk and meet some interesting girls and guys. One of which I went home with and we hooked up.
Not too long after I leave this guy’s place, I get a text from this guy, calling me a cunt, the whole “we're done" spiel as if I cheated on him. At the time I was apologetic as I didn't realise he had some form of attachment to me and actually felt kinda bad about it... Not long after, I realised he was fucking stupid. He said we could see other people, and didn’t object to us going to this guy’s house. He bailed on us and from what I remember I asked if I should go with and he said no. I was still single at the end of the day.
Had to get a ride home, I was really drunk and couldn't exactly go back to this guy's house.
Even had to wait for him to cool down before I could get my shit back though half of it went missing. He admitted that his sister took a few things of mine. Didn't want anything else to do with him so I just let it go as I got my tablet back and that's all I really needed to get back from his house.