Hi, I'd like to help you with your question.
The symptoms of Narcissism are as follows:
Believing that you're better than others and taking advantage of othersThinking you are more attractive or powerfulExaggerating your achievements or talentsExpecting constant praise and admiration
Lack of empathyDrastic mood swings in relationshipsTaking advantage of othersExpressing disdain for those you feel are inferiorBelieving that others are jealous of you and/or being jealous of othersDifficulties in relationshipsSetting unrealistic goalsBeing easily hurt and rejectedHaving a fragile self-esteemAppearing as tough-minded or unemotional
There is no split narcissism, although it may feel like that because a person with narcissistic disorder can react drastically different with different people. She can be nice to one person and hateful with another. It is all about manipulation and getting what she wants, either attention or so other goal.
Being in a relationship with someone who is narcissistic is very difficult. It can be better if the person has insight and is willing to work on their issues, but if not, you will always take a back seat to their drama and issues.
Trying to predict how to respond to a person who is narcissist is nearly impossible. Since they change as often as they see fit and their emotions can vary so widely, there is little you can do to affect them.
There are ways you can cope if you choose to stay in the relationship. Here are some resources to help you:
The Wizard of Oz and Other Narcissists: Coping with the One-Way Relationship in Work, Love, and Family by Eleanor D. Payson
Disarming the Narcissist: Surviving & Thriving With the Self-Absorbed by Wendy T. Behary
The Object of My Affection Is in My Reflection: Coping with Narcissists by Rokelle Lerner
You can find these books on Amazon.com or your local library may have them for you.
I hope this has helped you,