Is it weird that my boyfriend always wants his guy friend to go everywhere with us?

This could be for several reasons most of which aren't looking good for you. Firstly your boyfriend may actually be homosexual. If that's not the case then perhaps he doesn't want to be seen alone with you in public/ doesn't want people to know you are dating. Or on a happier note he may just like chilling with people and thinks the more the merrier! Next time you two go out on a date ask if it could just be the two of you.

I don't know what stage you are at in your relationship..if you are secure with each other, he does't see why his friends or relatives shouldn't be included in some casual outings. I wouldn't see any red flags in this.

If you're just getting to know each other, well, that is a little odd!1

I don't think it's weird, but it's inadvisable. He's trying to be a good friend and it's a wonderful thought, but he needs to appreciate your time together. I'd talk to him, but make sure he knows you're not attacking him. You're just feeling a little neglected.

He's gay? (kidding) Could be anything, ask him.