How old is your dc? Are the police aware of your visit to your GP and of his/her findings in relation to the beating you sustained?
Is your case being handled by your regional police authority's Domestic Violence Unit, have you been assigned an officer or worker who specialises in DV as your point of liaison with the police, and has a MARAC (Multi-agency Risk Assessment Conference) been scheduled?
As stated by PTS above, the CPS is a law unto itself and you're best advised to await the decision as to whether your ex will be prosecuted. Don't be tempted to drop the charges you have made and be sure to report any attempt(s) to persuade you to do so to the police.
In cases of common assault and assault occasioning actual bodily harm contrary to Section 47 of the Offences against the Person Act 1861 the Magistrates' Court is able to pass the same maximum penalty of 6 months' imprisonment for both offences but, also as PTS states above, first offences rarely result in custodial sentences being handed down.
As a victim of domestic violence you may be entitled to legal aid in respect of divorce proceedings and in obtaining any injunctions such as non-molestation and/or occupation orders which may be deemed necessary to protect you and your dc.
If you haven't made contact with, or been referred to, Women's Aid I would suggest you call and ask for recommendations for solicitors in your area who specialise in divorce and family law and have specific expertise in cases of dv. //www.womensaid.org.uk
If you are not minded to petition for divorce you should, nevertheless, take steps to ensure your h cannot return to the marital home until such time as he has attended a course for dv perpetrators and you can be reasonably assured that he will not re-offend. However, it must be said that courses of this nature do not have high success rates.
I'm so sorry that you've become a victim of dv and, in particular, I feel for your poor dc who witnessed their df's violent attack on you. This incident has undoubtedly been an horrendous shock for both of you. Talking helps - you'l find a lot of support here and I hope you'll encourage your dc to offload their fears, feelings, and concerns by talking to you.
for you, honey. No matter what your h may claim caused him to flip out, it is NOT your fault that he did so. Take care and go easy on yourself and the dc in the coming weeks.