The reason I post so many things on narcissism is because our culture has been hard wired to believe we never walk away from anyone, it is unChristian. But the Bible does not support that cultural premise.
2 Timothy 3:1-7, clearly states that when we encounter these self absorbed and dangerous personalities, we are to withdraw ourselves. Far too many people keep angry and destructive people in our lives, diluting our Christian walk and witness while working ruin on our emotions.
If the devil can keep us continually focused on how bad these people make us feel, often accusing us of things they are doing but we are not, he will manage to make us mental basket cases, completely consumed with their drama.
We can love narcissists from afar through prayer, we do not have to engage them in life. The day they act repentant, naming their sins specifically, while demonstrating brokenness over their attitudes and actions, then we can consider re-introducing them into our lives, however, even then, we must be cautious because they are masters of manipulation and often will feign sorrow when it is not real.
Let the Holy Spirit be your guide always. No matter what the situation appears to be, never completely accept it if the Holy Spirit sends you warning signals. Questioning a narcissist will reveal if it is real or not, a true narc who is acting will explode in anger at the suggestion that we need to see ongoing evidence before we can feel confident that this is real.
One who has been broken over sin, truly wants to be a new person in Christ, will accept this mandate to wait and watch for life changes. They will welcome it and embrace it as a part of the criteria for a relationship.
Never underestimate the ability of the Holy Spirit to speak to us warnings while knowing that He can also tell us if someone has truly been changed into a new creation by Christ, the Spirit within you will bear witness to the Spirit that dwells in the new creation.
1 John 4:1 "Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world."