I am so sorry you are going through this. It must be scary to live with an abusive man when you have a son. You don't have to make a decision right away. You can start to put a plan in place. When you call the domestic violence hotline they will refer you to a local shelters and tell you everything you need to get ready to leave. My previous husband was abusive. I had to slowly secretly gather everything I needed including an important document like passports and birth certificates.
The local shelters most likely have lawyers that can help you get a restraining order and divorce if you choose.
I am scared for you and your child. Please be safe. Abusers tend to get WAY worse when you try to leave. That's why it's important to get help from experts in domestic violence.