Hellsbells, it's not necessarily abuse, it could just be that he can't deal with confrontation. I'm like this and funnily enough it used to be my XH that would clam up and say nothing for fear of making things worse, now in my current relationship DP is the talker and I'm the quiet one! I know how frustrating it is to be on the receiving end but it's also hard when you're up against a formidable 'opponent' in an argument and I just shut down to protect myself.
Myfoof, I have tried counselling with both XH and DP - it was much more effective with DP because a) he talks! and b) we would talk about it afterwards, go for lunch and decompress a bit, then revisit things later when we weren't so emotional. I would come out feeling very emotional and touchy and I know DP felt very challenged at times too.
However, in the end we quit counselling as it was just an expensive way of bringing up things we'd already resolved ourselves in private. It did help in some small ways, but if he hadn't been so open and communicative this would have been the only way to get things out in the open in a neutral space. Talking about negative things is never easy, but it is necessary to move on, so either counselling or some sort of structured talking session, even if only the two of you making time and using some methods to ensure fairness and calm, is needed.
Stick with it, but give it a timescale and make sure you're talking in between sessions in a safe and respectful way too. One recent revelation we've had is that our arguments follow a pattern and that actually within the first 5 minutes we've both put our POV across, the rest is just escalating to try and convince the other to change their mind, which rarely happens and if it does, it usually takes 24 hours of pondering to really come to light, so whenever the actual argument ends isn't really the end.
I have said that if either of us feels uncomfortable with where a row is heading we should have a 'safe word' or some kind of signal to say, essentially, "I have heard you, you have heard me, we both love each other and want to be happy together. I will think about what you've said and if I need to modify my behaviour in any way I will do. Now let's be friends again."
I have yet to test it in battle, but I'm hoping that if it can diffuse things before they go too far it will be easier to talk about things afterwards when we're calm because we won't have both resorted to saying hurtful things to make a point!