Why is he acting weird?

So, basically my boyfriend visited his son with his ex in another country. We talked briefly on the phone when he landed. Then, a few hours later, he sent pictures and videos of his son. It looks like he's in his ex's house. He told me I plan to stay in a hostel but he didn't give me any details about it. He used to give me all the details and even send me pictures and videos in the past. We freely videocall and voice call freely, too when he's free. But in this trip, he seems different. It's his 2nd day in that country. From yesterday, he only texted me a few. I asked if he's free to talk since it's past midnight already and I know he's not with his son anymore. But, nothing. He said he'll just contact me soon since I told him I wanna talk because I wanna know some things. I said I understand. And just told him I miss and I love him and to have a nice day. He replied Kool only. But all seenzoned. After 40minutes. I repeated to send I miss and love him. But it's seenzoned again. I'm now heartbroken. I don't wanna speculate things. I trust him. But I'm feeling hurt right now. What to do?
Why is he acting weird?
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