Should I move out?

My stepdad and I have never really gotten along. Lately he and my mother have been treating me terribly. My stepdad has hit me a few times and my mom ignores it. They have kept me from leaving the house the best they can, even though I still find ways to get out. My boyfriend and his parents want me to move in with them so that I won't be in danger. I'm 17 and I want to go. But I'm worried about how mad my parents will get. There are also a 10 year old, two 6 year olds, a 5 year old, a 3 year old, and a 10 month old living at my house. My uncle also lives there and my older sister comes and stays occasionally. I'm not sure if I should leave because I don't want them to take it out on the kids. But I do want to leave because I don't like the situation. Any advice?