Sorry this is my first post, I'm borrowing a friend's login to post so I'm writing all over the place, sorry if it sounds messy lol

I'm 22, work as a barista in Hua Hin. Been with my boyfriend for almost a year. It's not a super passionate relationship but I do expect him to be faithful. This morning something happened and my heart just… dropped. Around 07:15 I went out to get breakfast from the stall at the end of the soi — it was only like 3–4 minutes. I saw him sitting with this other woman who I think I've seen on Instagram once or twice, not close at all. They looked way too close, like really close. They were chatting and laughing and the woman even rested her shoulder on him. I remember he was holding a white plastic bag with food and I glanced at my silver watch to check the time and I kinda froze.

I didn't want to cause a scene by bumping into them, but my mind is stuck on it. I feel betrayed and just stunned. Should I message him directly? Should I snoop through his chats? I'm afraid I'm overthinking or imagining things, or maybe I'm just sensitive — last night I lightly commented on his photo and he replied very slowly, maybe he was busy with work, I don't know. I just keep thinking about it and I'm so confused.

Sometimes I also think maybe I haven't been very open from the start, and now I'm mad at myself for not being more upfront. I'm asking you guys — if you were my friend, what would you do? Confront him straight up or wait and let him explain? What should I do T_T

P.S. If I'm just overthinking, please tell me honestly so I can calm down. I really am so confused.