Amy Dickinson is a general advice columnist.
DEAR AMY: Due to family issues stemming from my mother's death, I have severe trust issues with people. I don't like getting close to people because everyone I grew up with has either abused me in one way or another, lied to me about major things (such as the identity of my own father), or broken me down using my mother's death as ammunition. I am currently with a man I care for, but he shares his home with four generations of his immediate family. I find myself very standoffish when it comes to them, and even after a year I am only just starting to warm up to them. I find myself jealous of certain things -- things that I imagine are normal family things, such as having to share everything. For instance, when he and I go food shopping and then someone takes food we bought without asking, I am supposed to accept it. I need help or tips, something to make me "get it" instead of just getting annoyed. I grew up basically on my own and if I am to stay with this man (and I do want to), then I need to learn how to be more family-oriented.
-- Frustrated Introvert
DEAR INTROVERT: You might be less frustrated if you had a little space, privacy and property that you could count on as being yours, alone.
Getting annoyed after you shop for food and then find it has been consumed by others is normal, if not universal. I also think it is normal, given your background, to feel encroached upon when you are surrounded by four generations of a large family.
Ask your guy's family members, "Would you mind if I keep some things in this container that are just for me? It's my quirk from so many years of living alone." I also think it is important for you to have a physical space in the house (perhaps only a rocking chair in your room) that is yours -- where you can enjoy the privacy you seem to need.
Taking care of yourself will help you to conserve the energy required to interact with the rest of the clan. Do so with kindness and respect.