My Partner Won't Listen To Me - Narcissism And Selective Hearing.

Selective hearing is inherent in narcissism. It's as if they are listening FOR certain things, not listening TO others. They seem to be scanning for something they want to hear, for something they can USE, or for an opportunity to oppose, condescend, shame, or pontificate (i.e. dominate). They will tell you about themselves for an hour straight, speaking as if it's a reciprocal conversation (answering questions you ask and making eye contact), but as soon as you start talking about yourself they shut down. Some even act like you are "hogging" the conversation the moment it's not about them. If you make a joke, they will not laugh; they'll either re-tell the joke so they are the ones who get to tell it, or they'll act like it was stupid. If they do listen to you talk, their responses will often be unsolicited advice and condescension. They will give you advice from something YOU told THEM the week before, as if they just thought of it. They will argue and oppose you just to feel dominant. They will talk over you and try to raise the conflict and hostility level, and then say that it was you doing that when you raise your voice in response. They will insult you when they can't "win" the argument they started. They will change the subject even if you are in the middle of expressing something important~ actually, ESPECIALLY if you are. They will ask you 10 questions in a row and demand that you answer every one of them to their liking, but you can ask the same question 30 times and never get an answer. The only person a narcissist will actually listen to is a person who they think is "higher" than them in some way. And that may not last long if they become personal with them (when they find out that "higher up" is just a human, they'll want to dominate them, too, if they can). 
The only way to "fix" this is to understand it, and heal yourself from the effects of being treated like a ghost. A good couples counselor will be able to see this dynamic, but a bad one won't (because they may have the same affliction) so be aware if you go see someone. Healing for yourself is actually more important than healing this relationship problem, the other person may not ever change this, and it will take a serious toll on your health. Learn detachment, in other words, treat it like you would if you found out they have a different kind of illness that makes them behave erratically, that they can't help. Not the same as letting them walk on you; it's more like backing away and seeing it from a distance, or a bird's eye view, so you can see the whole picture, in the way you would with someone you don't know well. For example if someone told you their brother had mental illness before you met him, you would be aware of it, and not take his behavior nearly as personally. You would know he is coming from a place of illness, and that he can't help the way he behaves or speaks very much. You would have a boundary in place, and not keep trying to get him to treat you with respect or normal friendship. If he was over the top, you would put more distance between you and him, and naturally be cautious, but not judgmental, angry, or feel victimized. This is how detachment works, we unattach ourselves from the situation and person, and see them from farther away, instead of from up close. 

Kim and Steve Cooper have a course in curing Narcissism, you can find it here:

The catch is that the person with Narcissism is the key to healing it, they have to want to heal, which means they have to be aware that there's something "wrong".