Your narcissist owes you nothing. Their sense of entitlement invariably results in a "what's yours is mine and what's mine is mine" mentality. It also results in a loathing of accountability. They are above that.
Stockholm Syndrome – Adapting to Survive
survivors are in the relationship they cannot see what is happening to them. Being labelled "co-dependent" is unhelpful. And judgemental. One of the questions survivors are asked time and time again is "Why didn't you leave?". If the question is being asked then the door for education has been opened widely.
Mirror, Mirror: Narcissists and Envy
Narcissists are pathologically envious. You'd like to think they'd be pleased when you get that promotion or win the award but any perceived threat to their status as the only one deserving of attention, ever, is noted and brutally dealt with.
FOR PARTNERS
Your partner tells you he or she was in a narcissistically abusive relationship.  What to do with this information is of concern to you.  As with recovery for the survivor, psychoeducation is a powerful antidote to the hurt.  Currently, there is no specific diagnosis for this type of psychological injury but experts in the field are discussing whether Narcissistic Abuse Syndrome should be included in the Diagnostic and Statistical Manual (DSM).