is he cheating or am I too controlling? what should I do?

My boyfriend asked me the other day if he can go to his cousins ( a guy) to chill. I said I didn't want him to because I don't trust him And I'll be honest I got an attitude and he decided not to go. Tonight, his phone went off for hours, it never does so I was worried and decided to go over to his and as I was on my way I found out he had met his cousin and gone to his house from his brother. It's 12 am and I haven't heard from him since 8:30pm and I won't hear from him until he goes back home tomorrow. My question is, why would he leave me to stress about where he is all night like this and cause all this upset if he was just going to 'chill'. There seems to be something a little bit more interesting to make him do this. Or am I being too paranoid? I'm just so upset he's hidden and lied where he is and I don't know what to think 😢 could he be with another girl?😢 or do u think he's just with his cousin and he's done this because he knows I'll argue if I knew he was going there?