Hi TC
re your comments:-
"I think that partly I do hope that if I keep trying at the relationship that it'll get better. I don't want to have to admit that I've got it all so horribly wrong. I made the decision to keep this baby & people will think that that's silly if I end up a single mother before it's even born. I know that that's not a real reason, but I'm embarrassed".
I think your first sentence is a triumph of hope over experience. Relationships have to be worked on by both parties; he's seemingly not at all bothered at the way he's treating you, a non abusive person would not treat you in such a manner. You're in the wrong relationship and neither of you are suited to each other - don't compound the mistake further. You would not take verbal abuse from a friend so why is your man any different?. I have also seen what you've written about him up till now and he does not come across at all well.
"My parents & friends like him. They've never had any reason not to. He's generally a nice bloke - I really love being with him when he's on good form".
They probably don't tell you what they really think of him because you're blinded and probably won't listen to any reason. You've probably also told them hardly anything about him and certainly not about calling you abusive names.
How often is he really on good form?. I think you've only written that other sentence because you honestly cannot think of anything nice to say about him.
"My main concern is the baby though, obviously. I want to do what's right by it. I don't want to destroy the chance of a happy family life with its father, but I also don't want to bring it into the world where daddy spends most of his time sulking in the bedroom".
Sulking in the bedroom makes him sound like a petulent teen. He is truly an immature manchild. You're being dragged down by him now because you're putting up with all his nonsense he comes out with out of fear, a sense of shame and embarrassment (also misplaced). Do you honestly think he will change when his child is born; he'll likely accuse you of not being able to care for him/her properly. You'll be the one bringing up this child mainly alone as he won't tear himself away from his precious computer, uni course or friends. His life will likely carry on pretty much as before.
If you think you'll somehow get a happy family life with this man you are sadly mistaken because he will not change for you, your unborn child or infact anyone else. Staying with him because its somehow "easier" will do you and your unborn one no favours at all in the longer term.
How will you keep up your course once the baby is born?. Have you spoken to the University counsellors?. At the very least you should be doing this now and finding out where you stand.