Look up reactive abuse. What you did was reactive. I would also imagine that you are smaller and less powerful than him, so you losing it will not be as frightening to him, as him losing it will be to you. Your children also need to know that this behaviour is criminal.
I think you showed restraint to just smash his phone and not him btw. And I can’t believe after what he has done that he got aggressive and didn’t slope off with his pathetic tail between his legs.
Now you have seen behind his mask expect the mask to come fully off and the monster to emerge fully.
Im so sorry you are going through this.
Try and arrange some things for the kids so they are out of the house having fun and you can process. Wait until you feel more settled and calm before you decide what to tell them. Get some advice first.
Right now though you are in survival.
Firstly you have had a massive shock and your body will be reeling. Make sure you try and eat little bits when you can. Anything. I know you might not feel like it but lack of food will keep the cortisol and adrenaline high and make it harder for your body to come back down. Keep hydrated. Same reason. Cry. Rant. Scream. Etc when the kids aren’t home. Watch comforting things on TV. Whatever allows your body to feel
safer.
You will need an STI test at some point in the next week or so and talk to the GP about what’s happened and the impact on you emotionally - it will lay the paper trail of the emotional impact of his actions just in case it matters later on, and they can sign you off work and refer you to relevant support services. Also contact domestic abuse support. His actions are abuse and my guess is there is more. They will have all kinds of support available.
He sounds like a piece of work so if you plan to divorce him (I imagine you will) get paperwork together while he’s not there. Given his response so far I fully expect he’ll play dirty.
Transfer half of any joint account to your account. Get all bank account details. Where the money is etc. Get your and your DC passports and give them to a trusted person to keep safe. You’ll need your passport and marriage certificate to file for divorce. Get the house deeds, vehicle documents. Take copies at least. Anything precious to you, store somewhere safe. I don’t mean expensive items, just things he might know matter to you. Photos, sentimental things.
Good luck. Look after yourself extra well even if you don’t feel like it.