When the mask slips

I had a question to those that were married to a Narc. I recently read an article about a woman that was married to a narc and it said that they dated for 5 years before marrying. I also remember my xNarc saying that him and his ex wife dated for 3 years before marrying. What I'm curious about is whether you saw anything in all those years that didn't seems right, or did they wait all that time before letting the mask down?