Girlfriend (27) shared a bed with her best friend (27) and her best friend’s boyfriend (29)

Hi – for some context, my girlfriend of 4 years invited me to go on a trip with her and her friends. There would’ve been 3 couples, but I did not go. The plan was to get a hotel room with 2 beds and an air mattress. Since I did not go, my girlfriend’s best friend asked if she would be okay sharing a bed with her and her boyfriend. She said she has done it with the other couple who is in the room (although I’m not sure if she was in a relationship at the time). I know all of the people involved, but I still thought it was weird for that to be suggested.

I told my girlfriend I thought it was weird and she agreed that it was weird, so I assumed that they would not do that. I found out later on that she ended up sharing the bed with them. I trust my girlfriend and I know that nothing bad happened, but I can’t help be be upset that my girlfriend shared a bed with them. I’m not upset at my girlfriend, she did nothing wrong, but I feel like a boundary was crossed for me. I want to be able to move forward without this anger, but I can’t stop feeling upset imagining them in a bed together. My girlfriend told me her friend was in the middle.

I don’t understand why I am uncomfortable with the thought and why I cannot move on from this, but I would like to. Maybe it’s the thought of my girlfriend sharing an intimate space with another man? Maybe it’s the fact that there are 2 couples that are now aware of the fact that my girlfriend shared a bed with another man. I love my girlfriend and don’t want this to hold our relationship back.

TL;DR – girlfriend shared a bed with her best friend and her best friend’s boyfriend in a room with another couple, did not do anything bad, but I am upset at the thought of her staying the night in that bed.