Oh love, it is really not your fault. None of this is your fault. I could set fire to my dh's guitar (his pride and joy) on purpose, and whilst he would be justifiably angry, he would never physically hurt me.
If he's telling you it's your fault then he's not taking any responsibility. He won't change if he doesn't believe he needs to. Would you consider giving women's aid a call? They would be able to talk things through with you. If you leave a message with a time when it's safe to call you back, then they will get back to you as soon as possible.
I'm really worried for you. Please don't believe that your dc is safe. With my xh, I was so sure that because they'd never seen him do anything, that they weren't affected. One day I was sitting with them when he came home from work and started slamming things around (obviously in a mood), and I noticed that my 4 year old looked scared, and the older Ds was visibly shaking :( they didn't need to see the full extent to have learned to walk on eggshells in case of an outburst.
Are there things you could do to make it easier to leave when you are ready? Could you start a savings account and put some money away? Get together important documents like passports and birth certificates and keep it somewhere easily accessible? Maybe with a couple of sets of clothes for you and DC.
If he's casually this violent already, what happened when he really loses it? He already feels he has a right to physically punish you for not doing what he wants. Everything is replaceable except you and your DC 