The court can issue a witness summons to compel you to attend court and give evidence. However, this option is rarely used because a reluctant witness is often less use than no witness at all.
In order to secure a conviction without your evidence it will be necessary for other evidence to be produced to prove that your husband assaulted you. (Note that it is not sufficient to prove that you were assaulted � perhaps by means of medical evidence. The prosecution has to prove that you were assaulted by a particular individual).
If such evidence exists and a conviction is secured there is a very strong likelihood that the suspended sentence will be activated. Any offence committed during the period of suspension can lead to activation, though an argument against activation often succeeds when subsequent offences are dissimilar to the first.. However, in this case the later offence is identical, the victim is the same and it was committed within a fairly short time of the suspended sentence being imposed. In short, your husband has stuck two fingers up to the court.
To reinforce what Norman has said, statistics show that domestic violence rarely, if ever, gets better, only worse. Your husband needs to learn that beating you up will lead to prosecution and custody. You need to learn to live without him and the violence. This can only be achieved by you giving evidence.