I just want to sleep all day till my fiance gets home from work! His cousin is staying with us for a…

I just want to sleep all day till my fiance gets home from work! His cousin is staying with us for a week and we dont really connect too well so i avoid the living room so i dont have to sit in awkward silence with him...We share ZERO common interests and he mumbles really bad when he speaks so its hard to hold any conversation. I feel trapped in my own room. And now hes in the kitchen doing god knows what to the cabinet doors...Im hungry and want to cook but i dont wanna be stepping around him every three seconds....I cant wait for him to not be here any more...I feel like I have to tiptoe around him because he co-owns the house with my fiance because of their grandmas will. But he JUST turned 18 and i dont feel like i should have to be uncomfortable in the place that I call home because some teenager has legal rights to it. Ive spent the last two years trying to make myself feel comfortable here, and my comfort level goes out the window when hes here....I just dont know what to do...My fiance and his cousin get along so well that my fiance pretty much forgets that I need attention too and it gets old really fast...