Have a weird gut feeling not to trust bf of 5 months. He hasn't given me any reason not to. Help?

I've been dating this guy for 5 months and we spend practically every moment together. A few weeks back he wanted to goto a dub step concert with a friend of his who he has told me numerous times surrounds himself with strippers and X. Apparently this guy makes a habit out of feeding strippers X till they can't walk. My bf told me he would probably partake in the drug (no issue with the drug btw). My issue was the person he was going with and the fact that when my bf gets on X he's EXTREMELY emotional and touchy feely. I told him I didn't feel comfortable with him going and it turned into a drop down fight. Eventually he relented and didn't go. The bf says he doesn't support his friends lifestyle yet for some reason is getting involved with it.

A few weeks later a friend invited me to his shows after party. My bf brought up the dub step concert and used it as a reason why he didn't want me going so without a fight I said fine and didn't. Now tonight he texts me and tells me not to bother getting him from work cause he's going to a different dub step concert with this same friend and that I shouldn't expect to see him tonight. I don't want him to go for obvious reasons and do not trust his friend. I also don't trust him going to a rave on on X surrounded by strippers. I don't know if I can or should say anything or just let it go. I guess my biggest worry is that he's going to cheat. He has given me NO indication he's the type but I just have this weird gut feeling. Thoughts?

TL;DR boyfriend wants to goto concert to do X with his friend and strippers, I don't trust him but don't know why.

EDIT: he's 27 I'm 21.