Is is normal to not like when your significant other goes out?

I'm 18, and my boyfriend isn't quite 18 yet, Recently I went to a motel with my best friend to celebrate her birthday, I assured him there would be no alcohol, drugs, other people, etc. I made sure to update him on what we were doing. Yet before, during, and even after this trip, he said he hated that I went, didn't like the idea of it. Didn't give me a reason why he just didn't like it. I've tried to understand why he hated this so much, and before anyone says maybe he has trust issues, this is our first relationships, I've never cheated or anything of that sort. I put a lot into our relationship and honestly do a lot to make him happy by changing myself for the better. During the whole trip he barely texted and if he did it was dry because he said he was just "iffy". Is it normal for him to feel this way about me doing something like this? We have had many conversations but it always ends with him saying he will try to learn and become better. He told me later on after trying to understand why he felt this way he basically said "I don't know, I'm just insecure and immature then." Advice? Lemme know if you need more backstory or details
Is is normal to not like when your significant other goes out?
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