Idk what to do!

So Friday is our 3 month anniversary and I know it’s not a lot but it feels like it. My boyfriend has a really good friend and when I first met his group of friends they all warned me that they’re very close and almost don’t want to ever leave each other’s side, lol I thought. These past three months I’ve noticed it’s true and it’s almost like my boyfriend hangs out with his friend more than he does with me, I tried to be okay with it but I did let him know how I was feeling about that. There’s been times where it feels like he prefers to be with his friends than with me. They just recently went to a concert last min and he didn’t invite me (even though I was working that day, I would of still liked an invite) It makes me feel really jealous and sad. He knows bc i have talked to him about it, I want to bring it up but I also want him to figure it out.