Can a narcissist ever change? What if it isn't narcissism they have and there just very selfish as they are an only child?
Unfortunately not OP, they have absolutely no insight into their own behaviour and do not feel empathy so even if they could change, they see no reason to because they only care about themselves. Even if you cry and beg in front of them, they feel nothing but enjoyment of the power they have over you. What's worse is that they are utterly convinced of their own perceptions (I.e that they are the victim and you are treating them unfairly by asking them to do things they dont want to. You cannot reason with them and you cannot explain your point of view. The best analogy I've heard is that they see you as an object which they own, for example if you are their right arm and their right arm stops doing what they want, they will become angry and frustrated because it is THEIR arm. They do not love the arm, the arm is part of them and they must control it.
Also, narcissists are essentially in survival mode. They need narcissistic supply to feed their fragile ego. By acknowledging your feelings matter, it's like to them like saying they dont matter at all (which is the ultimate fear of the narc).
Its common for your mind to play tricks on you and start doubting whether they are abusive. Thus is called cognitive dissonance which is essentially your mind finding it too painful to accept the truth so you start to find reasons why he is not abusive.
If he was just a selfish person, he would be able to have empathy for you and there would be some way of getting through to him. You know this isn't the case because of his actions. His words are all bullshit to keep you under his illusion. You also need to ask yourself why settling for a selfish person is acceptable to you. Why would you even consider settling for anything other than love, trust, care and respect. This is the crux of your issue.
I agree you dont necessarily have to be codependent to attract a narc but you certainly have to be an empath who wants to fix people. Also, I agree that everyone attracts narcs to an extent but only deeply damaged people stay long enough for the relationship to destroy them (whether they were already damaged or damaged from narc abuse).