Typing on my phone at 5am, sorry if this is all over the place.

Woke up yesterday and couldn't get my head into my research, so I'm dumping this here to ask you guys if I'm just being paranoid or if something's actually off. I'm 31, doing a master's in Bangkok but living in Hua Hin, doing research with a prof and teaching part-time.

Short version: I'm so confused.

We've been together almost three years. We started dating before I began the master's. Mostly see each other on weekends, eat around the lanes near home, plan a trip out of town once or twice a month, split gas and coffee and stuff. I felt like she really understood when my research stressed me out. But in the last two months some behaviours have slowly made me suspicious.

It started with an IG story she posted around 10pm-ish saying she was joking with an “old friend,” and someone commented laughing. I didn't make a big deal at first but she started putting her phone away a lot, not letting me touch it. When we're together she’s often buried in group chats or Facebook. When I ask she acts chill and says it’s work or old friends. Fine. But the guy who shows up in her stories a lot is someone I’ve never talked to, and she seems closer to him than she ever said “just a friend.”

Two weeks ago I had a meeting at the university and had to stay in Hua Hin for a night. She said she’d go visit her mom and come back Sunday, but Sunday morning someone tagged a photo of two people at a cafe near the Hua Hin beach — her and that guy smiling sweetly, looking more close than just play-friends, with a cheeky caption that only the two of them would understand. I was confused because the cafe is in Hua Hin but her mom lives in a different province. It didn’t add up.

I started noticing more stuff: late-night chats, messages that get deleted quickly like read-and-vanish, statuses she hides from me even though she usually posts stories I see. Once I saw a reservation history with the booking name not mine. She said it was a university friend, but why book places in Hua Hin late at night so often? My mind went wild from there.

I’m a straightforward guy, so I asked directly. First time she laughed and said I was overthinking, that the guy was a friend from school who helped with things, that the stories were just banter. I wanted to believe her, but not telling me she was staying in Hua Hin — even though she carries that little red keychain and is at home — didn’t sit right. It felt like small secrets piling up into a big one.

She’s changed how she dresses, cares more about looks lately, and when I send photos she answers slowly and holds her phone longer. Sometimes she replies with stories that have the same looped hinty vibe. It sucks seeing your partner get close to someone else. I don’t want to be controlling, but I feel pushed out of the trust zone bit by bit and I’m starting to doubt her sincerity.

When I brought it up seriously a second time she got mad and told me to stop suspecting her without reason, that it’s damaging our relationship, then she went quiet for days. I felt bad for causing a fight, but I couldn’t stop doubting. I asked to see her messages and she refused — everyone says that’s privacy. I’m stuck.

Maybe I’m just overthinking. Maybe she needs more personal space. Maybe there really is someone new. I don’t want to lose her, but I also don’t want this uncertainty wrecking my research. I get so stressed I lie awake two hours and can’t do anything, toss and turn at 1am or 2am.

Anyone who’s been through this, be straight with me: what should I do? Trust and let it go, or ask for clear proof? What questions should I ask to get honest answers, not just brush-offs? Give her time or push until I get the truth, because I’m scared that dragging this out will wreck my mind and my work.

I’m really confused T_T haha

P.S. Sorry if this post is out of line, I just want an unbiased view. What should I do?