Why do you want to be someone who lies to you, cheats on you, etc? No amount of understanding them will change that they do these things to you.
Also, please stop saying you're not judging, because that's all you're doing about actual NPD people. You say "i know he's NPD because of these traits" and then you list all these horrible things that you associate to NPD and say "this is why I know he has it."