I don’t know how to leave

I have no idea how to explain this but I want to leave an abusive relationship. I’ve wanted to since I was pregnant and he started all of this up. Literally nobody believes me when I tell them. Even after telling them about the horrible things he’s done. All I ever hear is “he would never do that” or “that is so out of character for him”. He got charged with a PFMA when I was pregnant and still it was “he couldn’t have”. I stayed. I shouldn’t have. It’s been a year and a half. He yells at me in front of my son and that is what makes me the most upset. He threw his phone earlier this afternoon, it hit me. He threw my phone tonight and left a hole in the drywall. I was so afraid when he threw it that it was going to be at me with my son sitting in front of me. I CAN’T stay in this relationship anymore but I’m terrified to leave because I don’t think my parents would even help. Nobody believes me. Even when I have proof.