I think every person has narcissistic traits. It's necessary for survival. I think you are probably less narcissistic than average, which is why you've put a lot into a relationship that hasn't served you so well. Codependency is almost opposite of narcissism...and I would guess that you have a bit of an issue with codependency, and in this situation your in it's actually important to be thinking about what you can get out of it for yourself (thinking more like the narcissistic one, basically). Hope that makes more sense