Background

I've made a post a few days ago which I deleted (privacy reasons) describing how my LTR went on a 10-days trip with 2 girlfriends and 1 guy friend she kinda knows from highschool. The latter, as far as I know, is not really a threat cuz she knows from highschool a while ago. After graduating, she and all of her friends went abroad to study in Europe, so now they're visiting each other once in a while when they can. This guy visited her once, they hanged out, and she uploaded a picture of him on Instagram thanking him for coming and asking him to come again. I figured he couldn't get deeper in the friendzone.

My concern in the previous post was that in the last city, her female friends are leaving and she's staying with the guy in the city 1on1. Not sure in a hostel, Airbnb, or a hotel, I didn't ask after she told me this, thinking I'd come across as insecure.

But anyways. It was discussed well in the previous post, and I just came to the conclusion that if she wanted to fuck him, she would, and I can eat a dick. Seriously no need to focus on this point.

My concern

After she left we kept texting casually and on her last night in the first city, she sent me a few pictures (best of stuff she promised she would do after every city she visits), so I called her and we talked over Messenger.

She was having a flat party in the Airbnb she was renting with her friends, and she was fucking drunk. She could barely speak English. A lot of shittests. Laughing for no reason. But we had fun nonetheless until something happened which fucked me up real good.

Someone knocked on the door and she had to open it. She asked me to wait a little. I have no fucking clue who it was or what happened, but she opened the door, and she was laughing shyly, (wtf?) and I have no idea what to make of what the fuck I heard next, but it did sound like... kissing? Or am I fucking making this up? I don't know, the sound quality was trash. But I mean what the actual fuck? Could she have fucking kissed the guy while on the phone with me? The person didn't utter a fucking sound. So I dunno who the fuck it was or what they wanted. I heard the door open, but I didn't hear it closing. So the person defintely remained in the room. I heard her steps coming back towards the phone, but absolutely no footsteps from the other person leaving or entering. "So, what was I saying?" she continued casually.

This can't be happening... right? I mean, she can't be that fucking dumb to actually blatantly cheat on me while I'm on the phone with her... right?

I just got super anxious, conversed for a little and hanged up. I have no idea what the fuck I had just heard, and I didn't know how to handle it so I ghosted her for a day.

Current Situation

Hit her up on text today, asked her if we could talk, I have this new song I wanted to show her. but she said she can't cuz there's no space in the room they're renting. It's a part of a big house, and the owner is there sleeping. I said she can always go to a corridor or wherver and talk. She called me a few minutes later from the stairs saying that she can't really talk cuz they're sleeping, and here I am. So we conversed for a while and let her go. She's calling em tomorrow from the hotel in the next city.

Guys, I seriously don't know how to proceed from here. I brushed off the phone incident and didn't even mention it or think about it. I just thought it was all just my fucking imagination... But is it?