I 26M have been with my girlfriend for a bit over 2 yrs. We live separately but she's been spending most days at my house. I eventually gave her a key to my place. I'll come home from work and most of the time she'll be there.
She basically lives there. Has a lot of her belongings there,showers, sleeps there,etc. She has 4 sisters. 2 younger, her twin and her older sister. Her older sister has a 2 yr old daughter and is a single mom. My girlfriend has been asking if her sister could come to my house to hang out. I have no problem with it so I say sure.
Here's the problem. I got home Thursday. When I got inside my girlfriend was with her niece. I greet my girlfriend and niece. When I start walking to my bedroom, my girlfriend tells me she set out clothes for me in my gaming room. I ask why? And she says that her sister is taking a nap in my bedroom.