Advice! Sorry for the rant!

Ive been thinking about this for quite a few months now. But, my boyfriend of 3 years (we are both 17 an will be 18 late this year/early next year) wants me to move in with him because he doesn't like how my grandparents and my cousins treat me. I do most of the chores and take care of the kids 90% of the day everyday. And they constantly bitch at me (sorry about the language) about everything. My grandfather isnt usually home unless its dinner time and when he is home he yells an bitches at me about Everything that I did wrong. Ive lived with them for nearly two years and im sick of how the kids treat me, and im sick about how my grandparents yell an bitch all the time. An I think that my grandma buys stuff for us to make us love her. An that kinda annoys me. I just dont know what to do an I need advice... sorry for the rant... its only half of my issues right now.