I'm not sure about the timescales here, and i think they make a difference.
Are you saying that for the past two and a half years, ie before the pregnancy, he has been being horrible to you, and that it has got worse as you have become a mother? Or are you saying that you have been with your husband for two and a half years, and that at some point in the relatively recent past, he has started being horrible to you?
If it's the former, you sound as if you are describing an abusive relationship, that is getting more and more out of control. This is following quite a common pattern, that the abuse escalates during pregnancy/motherhood. Go to Women's Aid for some help. This situation will not improve.
If it's the latter, then there is a chance that this is salvageable. Having a premature baby is a shocking, traumatising experience, for both parents. It puts a huge strain on a relationship. There is the possibility you are both depressed. You will certainly both be exhausted and emotionally drained. Are you still in contact with the hospital? There are support services for parents of premature babies. You should also ring your Health Visitor, and talk things through with her.
How you view what's happening depends a lot on when your husband's behaviour towards you actually started.