Everyone messes up every now and then, but narcissists give flimsy excuses rather than actually following through with promises. When their actions don’t match up with their words, they shrug and say they weren’t really thinking about it. You’d be humiliated if you broke a promise, but they are emotionless and it simply isn’t a serious problem to them, even when you point out that they are destroying the all trust in your marriage and that the marriage can’t survive without trust. They know that, but it’s irrelevant, whereas once, it was extremely important to them…but that’s long gone. You are disappointed so frequently that you can’t feel relieved when they do something decent—they condition you to expect to be disappointed again and again, and you are. All happiness is temporary, and just a short reprieve before another inflicted hurt.