My gf invited 10 guys to her bath tub

Edit: not naked in a inside bath tub, a jacuzzi like bath outside with bikinis* sorry for confusion, hard to explain in short title

Edit: Im making edits below with questions and answers from the thread so new people can see. P.s for people asking, Im definitely over her. I wish her all the luck in the world, I respect her, but I have no feelings for her and it was I who insisted on staying broken up. This is purely for some self introspection, its always good to learn and see where you did wrong.

My ex and I are broken up, this happened years ago and I want to know if I was the asshole.

Long story short, my gf was abroad with a couple of female friends, both single and /taken. They had gotten a small boat, and were out on a lake. They saw a bunch of guys, roughly 10, on another boat, and invited them over. I’m not sure exactly but I’m 99% sure she did the inviting, or atleast very happy about it. In her own words, “she likes to meet people” . They had a small “bath” ring behind the boat (think jacuzzi that floats on a raft, with sea water inside), and they all bathed in it.

I woke up at around 11 pm of her sending me a picture of her day, her in this boat ring bath with 10 other guys and one of her girlfriend. I asked who the guys were, and she explained. I didn’t react well, hung up, and a fight ensued over text. We mutually broke up a week after after having a "need to think about our relationship" week from both sides.

Now several years later, was I the asshole? Is this just normal and am I being possessive? I can’t see myself see a bunch of girls in bikinis and feel comfortable just waving them over if I have a girlfriend, I feel like that’s cheating

Edit: I want to paint her in the best light possible here (all of this Im just guessing, but if I were to take her side): From her perspective she didnt necessarily lead the invitiation, it was her friend. Meeting new people should be ok in a relationship and you dont ask for "permission". She told the guys she has a boyfriend. Trust is important, and she communicated clearly about her day and didnt hide anything. Her having fun with other people shouldnt be a cause for concern in a relationship.

Edit: Ages me 29 at the time, her 26-27

Edit: To paint a clearer picture, it was her, her friend (sitting beside), and their friend couple (guy and girl) stearing the boat. So it was her, her friend (status unknown) with 10 guys. I dont know which of the two did the inviting, but my ex was very outgoing and liked meeting people, so it was probably a joint decision if I were to guess

Edit: "Tub description": It was a ring full of water, with a floor, a seating area around it, and walls to keep the water in, that floats on the lake sort of, hard to explain so I just used simple terms. It was a ring and people could sit in it. Just imagine a jacuzzi on a raft but without (I think) any hotwater, only lakewater taken in from outside. People sat in bikinis and swimpants

Final edit: Happy to see it seems to be about 50 50 yay nay, always glad to hear some feedback. Since ive tried my best to paint her in a good light, Im gonna be a bit selfish and paint why I felt that way with her. She had cheated before ON AN ex (so not on me, 5+ years ago), and she was never really outspoken about her liking me. Only time I heard she liked me was through her friend saying "she must like you, she hasnt done that to alot of guys". I felt abit unloved in the relationship, so it probably didnt take much to push me over an edge. Doesnt make me "right", just food for thought

Edit: kind of this? https://www.spacruzzi.com/ it’s hard to say exactly since I just saw a picture

TLDR my ex, her gf (status unknown), in round bath tub on a raft behind a boat on a lake, invited 10 guys from another boat to sit with them. All wearing bikini/swim pants. She most likely invited the guys (based on our convo after). "She likes to meet new people" her words. I dont think she cheated, maybe just crossed a line. 3 month relationship. 29M and 26F. Wanna hear your thoughts