Boyfriends brother ALWAYS there... affecting relationship

So my boyfriend recently moved back into his parents house, which is totally fine I get on really well with his family. I actually met my boyfriend though his brother as we are friends.

But his brother is always there. And my boyfriend completely welcomes his presence. Whether it’s watching a movie, getting dinner, he’s just always with us.

My boyfriend often avoids seeing me or plain ignored me for his brother. Like I could ask him to go shopping or hang out and he’ll say no he’s staying home and then he’ll end up going out n doing something with his brother.

For example, I was just in their house and we were going to order food, but because I couldn’t decide what to get (I have no idea why they made me responsible for deciding anyway I wasn’t bothered) my boyfriend got frustrated and said “well I’ll just take you home then if you can’t decide” AND HE DID. And I’ve just seen on his brothers Snapchat that they’ve gotten food anyway.

All my friends think it’s weird and anytime I bring it up with my boyfriend he’s like HES MY BROTHER WE’RE ALWAYS GOING TO BE BROTHERS IM NOT GONNA STOP BEING BEST FRIENDS WITH HIM. which obviously isn’t what I’m asking him to do, would just like to spend a day with my boyfriend alone and not be thrown to the sidewalk.

Sorry for ranting but it’s really upsetting me now