He has a fucking cheek to be messaging you at all! Absolutely flabbergasted at the brass neck of someone to beat the shite out of you and have the audacity to ask you for anything when you leave. Trying make it all about him with fucking sob stories. It's horrifying op and I'm so sorry you're going through this.
I echo prior posters about reporting this to the police. Because there may come a time where you have to show he has been abusive in order to better protect your kids. It'll help you a great deal to have on record what he has done even if they don't pursue criminal charges.
They should though, men who assault women, let alone to this degree, should be locked up so they can't hurt others. Or, their kids. Whats to stop him beating your daughter up if he gets drunk some night? And don't say he wouldn't, because last week you'd never have thought he would attack you. And no, you staying would not protect the kids, they'd just witness their mother being abused forever, not being able to help her, and grow up thinking abusive relationships are normal.
Protect your kids, get the assault on record. That way it'll be easier to get them away from him if and when necessary. Tbh...I'd be going for full custody now on the back of, you know, him being a violent piece of shit. Its not as easy as all that of course but seriously the only way to protect yourself from his kind is to have a strong offence.
Do not negotiate with terrorists, as they say. His sort take kindness and compromise as weakness. And they attack weakness.
If your children are older then of course they can just refuse to see him. If they're older I'd probably tell them why you left and that they don't have to see him anymore either if they don't want to. He'll probably give it the 'Oh she's keeping me from my kids waaaaah' to all and sundry but, who gives a fuck. Let him winge. He probably won't take you to court for custody if he knows you'll tell the judge what he did. Even if he does, the court will take older children's choices into consideration if they don't want to stay with him anymore.
Buy if your kids are young, definately go to the police. Tbh I'd go anyway. He broke the law in one of the worst possible ways anyone could. He belongs in jail.
Get yourself that gp appointment and tell thrm the truth at the very least. So there is official record of what he's done somewhere.
Well done for getting out. Never go back. Next time he could kill you.