bf obsessed with his family ??

This may be me being melodramatic but my boyfriend ALWAYS wants to do stuff with his brother !!
Like if we've planned to out to dinner then his brother asks us to dinner, we will end up going out with them instead of Just us two!!
For example, tonight we were supposed to being going out just us two and I'm sitting getting all dolled up and he just texted me saying we are going out with his brother and his pal instead ? Like am I being crazy? but this is just so annoying!! Help me out ladies 😢
Update:
I've told him before how I feel about spending time alone as well as with his family considering, he along with his family are more than 4 years + older than me making me feel so out of place :(