idk if I'm being hormonal or not but I'm pretty mad! My bf wants to go pick up his 17 Yr old cousin…

idk if I'm being hormonal or not but I'm pretty mad! My bf wants to go pick up his 17 Yr old cousin to come stay with us for God knows how long. It happens during breaks and summers and I hate it ! He ends up being here for like a month. Well it's just really bothering me now because we don't have much longer till it's not just me and him anymore for a long long time and he's just not even thinking about that. but if I say something he's gonna bitch me out and get butt hurt