Live with my bf and his family

So usually his mom provides everything starting from food and toiletries. Don’t really mind because when my bf stayed at my house my parents did the same thing. Furthermore, they have my bf a car and other shit. I know his parents can’t provide me with the same things and I don’t care. It just kind of gets annoying when I buy my own shit and his sister uses my stuff. Like really? You’re a 26 yr old mom. For example, she had money to buy shit she needs and she doesn’t for who know what reason. I bought body wash and she was using it like it was hers. Then I got an oil for my hair and all of sudden she was looking for that same oil and couldn’t find it. Lol Voila she used it. Thoughts ???