Sneaking away from my boss to post this, I’ll come back to work at 1:30 pm later lol

I’m 34, I do accounting at a small office in Nakhon Ratchasima. I’ve been with my boyfriend almost three years. Mostly everything’s smooth, not many problems, but lately I’m getting really unsure. Super confused.

So last week around 12:30 I went to buy a made-to-order lunch at the stall at the mouth of the soi near work. I saw this woman sitting at the same corner table my boyfriend sometimes sits at. She was kind of avoiding attention, like didn’t want anyone to see her. When my boyfriend walked past he sent the same sticker pack he’d sent me that morning (I clearly saw it on his tiny phone screen). I didn’t say anything because I didn’t want to make a scene, but my heart was racing — I almost fainted standing there for like seven minutes.

The next week I saw the same woman at Central near my house, and last night I saw a photo on my boyfriend’s Instagram story — the lighting and angle were the same as the place that woman had posted from. I asked casually, “Who is she?” He replied briefly that she’s a coworker, they just bumped into each other at a work party, nothing going on.

What’s weird is he’s been disappearing suddenly more often. He gives explanations, but the coincidences are piling up. I don’t know if I’m overthinking or if it’s just my instincts. I want to trust him, but there’s a little voice nagging me every night, biting my pillow. I’m scared to ask directly and start a fight, and I don’t want the work atmosphere to get tense either — he doesn’t want that for the office.

What should I do? Do you guys have any polite ways to ask that get a clear answer, or should I stay quiet and wait for things to become clearer? I want to talk without yelling or getting emotional and actually get a real answer. Tell me your ways please haha T_T