I feel like my boyfriend has 2 girlfriends ☹️

My brother in law lives with us and has forvthe past year or so and fir the rest of this lease which is like 8 more months and so me and my boyfriend never have any alone time anymore. His brother doesn’t work so he’s home 24/7 and they’ll sit and watch sports or go out and play sports all day every single day and they start making all these life plans together that me and my SO were supposedly already had planned for OUR future as a couple. They just start coming up with their own thing and they talk and talk and never ever listen to what i say so its like im not even there like I’m invisible and talking to myself and i just always feel super unincluded with everything. I just feel like its super annoying and its making me want to be just distant and alone since thats how im feeling anyway. I just want to live with my SO alone and start our life together but i feel like he always has to include his brother and doesn’t get that in a relationship we cant always live with his brother. I feel like we want different things. I want to settle down and i think its clear that hes not ready at all☹️ what do i do? Would i be overreacting if i moved out?

I feel like I’m in high-school again with cliques which even then i was always left out I’m reliving hell😩😩

Im 20, SO is 23 and BIL is 25