Well BS77, perhaps you could think about this the other way around.
If someone does something that upsets you, and there are then no consequences for them as a result of this behaviour, then why should they stop? If they like the behaviour, or it gets them their desired result, and nothing happens to them to stop them...they are not going to stop.
If the consequences are worse than the reward for them, then they may think about changing. For example, a man who is violent to his wife and children may think twice before kicking off to some large bloke in a pub, for obvious reasons.
Your partner doesn't think that he needs to change until you get so frustrated that you blow up at him. Then he feels the consequences of his behaviour. He may change for a while, or he may change for ever.
This brings us back to the making of an N, if a child does something that is not desirable, the parent has to show the child that there are consequences to that action. The best learning experiences are those that show you the consequences that come about from your own behaviour. eg you can tell a child until you are blue in the face that if they touch something hot it will hurt, but until they actually find this out for themselves, their behaviour may not change. The problem for Ns is that the messages they receive from their parents/carers are completely mixed up, and the consequences of behaviours can be totally over the top, or none existent. They are certainly not consistent.
Some research has suggested that actual neural damage occurs in these people when they are children, and that this can never be righted. Certainly in my experience, of my father in particular, I would agree with this
The trouble is that most people learn that actions have consequences as children. But people who have no empathy for others, just carry on regardless, as the consequences of them not thinking before they speak, and so on, are not bad enough to make them stop.
He is happy, and if you are not then tough luck. Why should he change, until he absolutely has to?
It's like training animals...they do one thing, they get a reward, they do another, they are ignored. This trains the good behaviour. But who wants to do this with a grown adult? Particularly one who is supposed to be your partner. This is how you teach toddlers, not grown men and women!
Its a very complex area, and is only really becoming more understood recently.
These people have always existed however, but only you can decide if you can live the rest of your life like this or not.