When is the next hearing?
Have you received any help from Victim Support www.victimsupport.org ?
If the case goes to trial you should be allocated a witness care officer who will support you throughout the proceedings.
However, I'm somewhat confused about the charge and your mention of a possible trial. Are you absolutely certain that he has only been charged with 'common assault' as opposed to, say, causing actual body harm?
I'm very sorry but, sadly, unsurprised to learn that the support you've received so far has been useless less than satisfactory and that you feel you've been 'thrown to the wolves'. It is lamentable that so many victims have to effectively source support for themselves at a time when they not be best placed to do so - hopefully others may come forward on this thread to provide the words you need to hear.
Was the DVS worker allocated to you by Women's Aid? Regardless, I would suggest that you search 'womens aid' followed by your county or nearest city/town and call your local branch with a view to attending support groups or being put in contact with other women who are/have been in your situation.
Do you have non-molestation and/or occupation Orders in place? How is his anger at being held to account for his actions being manifested to you? Is there any reason why you are required to have any face to face contact with him - eg his contact with dc, etc?
If you are unable to access the support you may feel that you need, you could ask your GP to refer you for counselling although, given the demand for these services, it mat be that the case will have been heard before you get plugged into the 'therapy system', so to speak.
Notwithstanding any support/counselling you are able to access, I would suggest that you try not to think ahead to being required to give evidence against him. Try to focus on the immediate future and what you intend to do after the case has been heard.
Needless to say, you chosen the only path that it is feasible for anyone to take after they have been subjected to an assault of any kind and where the CPS/police have determined that charges should be brought against the perpetrator.
You may feel that you will not benefit from him being brought to account but you can sleep well at night knowing that you have done your civic duty and, hopefully, spared the next unfortunate woman he takes up with the ordeal that you have endured.
Your courage is remarkable - I can only wish that more victims of dv and more police authorities were as equally determined to bring abusers to account in law.
BTW, have you enquired as to whether you have a claim to put before the CICA, or whether the criminal court may make an order of restitution in the event that he is found guilty? NB in respect of the latter the you will need to talk to the CPS barrister who has been assigned to prosecute the case.