Slapping him was not OK, but if he responded with serious violence, that's even more not-OK. He's legally allowed to defend himself, but not beat you in response to a slap.
I'd suggest contacting the National Domestic Violence Hotline or your local women's shelter and speaking with an advocate. I'd also suggest getting some legal advice. If you can obtain a protective order, it's possible you would be able to remain in the house temporarily, at least, while he would have to leave. What happens with the house and with other property would depend on the divorce laws in your state, but without legal advice you won't know what your rights might be.