Do you love the narcissist? Or are you in love with your fantasy of what you wish the narcissist to be? How can you tell whether you love the person or the fantasy?
The following applies not only to romantic relationships; it applies across the board of all relationships including parent/child.
You can not truly love someone until they have revealed their characters to you. Why is this so? Because who we are is revealed by what we choose to do. Our characters are the sum total of the choices we've made.
Until you know someone's character you can not say in truth that you know or love who they are. This explains why so many marriages fall apart. People fall in love with their imagined version of the other person and don't become acquainted with that other person's character until enough time has passed for the consistency of their characters to be revealed. This is why short dating periods are often disastrous in the long-term.
We each have a will. How we exercise our will = the choices we make. The choices we make = our behaviors. The consistent behaviors a person exhibits is the truth of who they are. Behaviors are the revelation of character. Behaviors reveal what has been happening in the unseen realm of someone's thinking. When a person, like Cho of the Virginia Tech massacre, suddenly went on a murderous rampage, he was not acting out of character. He revealed what his character truly was. We have a sudden, horrific and stark revelation of what his thinking and small choices have added up to. What Cho did is who he is. Cho forced us all to see what an evil character had been developing quietly step by step and choice by choice while no one was really looking. We often hear people protest after being caught in some bad behavior that "it isn't like me to do this". No, it is like you. You chose to do what you did. You revealed who you are, not who you aren't, when you cheated on your husband or when you cooked the books at work.
If, after having a clear view of someone's personal character traits, you have respect, admiration and trust in that person then you can correctly state that you love this person.
Then there is the situation where you have gotten to know the personal characteristics of an individual, and you find that you can not say you love those characteristics. Yet you insist that you still love the person. Never mind that this person lies to you, cheats on you, slanders you to others, even physically abuses you...you tenaciously insist you hate their character traits but you love the person. It is this so-called "love" which justifies why you are still in this bad relationship. Whatever the reason for it (there can be many), this is describing someone who has created a fantasy around the objectionable character. They are not in love with the person...they are in love with the idea of who they've decided this person is in spite of the evidence to the contrary. This is not reality-based thinking. To insist a person is "good" despite what bad things they actually do is an exercise in your imagination only.
Perhaps you insist that you love what this person could be if they only tried. This, too, is a refusal to live in reality. Can we please dispense with this sloppy thinking? Can we stop trying to fool ourselves in order to justify staying in a destructive relationship? Can we call things by their right names? Go ahead and insist that you love the rotten character, but quit doing it to make yourself believe you are a better person for doing so. Stop white-washing their character in order to convince yourself you need to stay connected to them. If you are afraid of leaving the comfort of the known for the discomfort of the unknown world of life without this bad character, then admit that truth to yourself. But stop pretending you love something that is hateful. Remember that a key component of mental health is the mind which insists on living in reality i.e. the truth. You are not doing your mental health any favors by engaging in these mental games which allow you to stay in a bad place. If you don't love what a person does then you can't accurately state that you love the person himself.
This type of imaginary love is a real problem for many adult children of narcissists (ACONs). It can be incredibly difficult to admit to yourself that you don't love your narcissist parent or that they don't love you. It seems to go against nature to make that admission. I see many ACONs insisting to themselves that they love their N mom or N dad despite the decades of ill treatment they've received from her or him. The ACON isn't ready to give up the idea of having a loving parent, so the ACON must pretend they love this abusive parent in order to justify staying connected. They are willing to pretend that their mommy or daddy really loves them "deep down" though they don't recognize they are having to imagine the love they "see" coming from their parent. This keeps the ACON in an actively destructive relationship. Many ACONs are willing to risk their marriages and their own children's emotional and physical safety in order to "keep the dream alive". This refusal to admit to reality is damaging to more than your own mental health. You can risk everything good in your life by insisting your fantasy is reality. Your refusal to walk away from a destructive parent is not a testament to your deep and abiding love for this person...it is a testament to your volitional stupidity. Do not call your dependency on a bad relationship "love".
It is okay to love a bad person, but only from a distance. Don't insist your love for a destructive person is justification enough for staying close to them. You risk all that is good and beautiful in life in order to love the unlovable. Maybe you think that means you are a better person because you can love and unlovable, but when your so-called love means the destruction of your own well-being, and the well-being of the innocents around you, then I insist you are not as good as you think you are.