L.W.
Sounds like you went from one abusive relationship to another. Your mom is still abusing you in a way by what she is telling you. What she said about you being single for the rest of your life if you were to divorce is simply not true. You need to get out of this marriage for the sake of your child and yourself. Especially if he refuses to get the help that he needs. He's the one with an anger problem.
Sure it's scary to be a single mom but mom's do it all the time. It doesn't have to be as scary as you think. I've known some brave hard working and stable single moms. I've been one. It's not easy but it's doable. It's healthier for the children to be with a strong single mom than it is for them to be in a house full of hurt and anger.
I'm sorry you are in this situation. Wish you all the best.