Are narcissists only narcissistic when they are triggered?

Curious what others opinion is on this. My husband gets super abusive when he is triggered and seems okay when he's not. I think the thing is though you never know what is going to trigger them or set them off. One thing I have noticed in the last little bit is that they do know their behaviour is wrong which is why they don't want you to tell other people and also they justify it so they don't have to change.