Well empaths may have issues with trusting others because they can sense a lot of lies growing up, so first of all try not to hide your feelings is an idea I got I am not some relationship therapist so these are just ideas. She could be afraid from disagreement because she may sense hostility or something for all I know. I think it is mostly like dealing with a regular person but just don't lie and don't suppress your emotions if you are not feeling pleased we can notice that. Try to keep your emotions without being attached to them, if you can. That is a tough technique that takes a lot of discipline but it is possible. The huge wall, idk what caused it, but it seems logical for it to be based on all the lies empaths sense and such, I also have a wall that I have let nobody in. It could be she is afraid of being rejected, empaths tend to be betrayed when they are very altruistic so rejection is something certain empaths may face a lot.
People are not comfortable with arguments when they don't trust the other person or they cannot process the emotions mixed in conflict well. To diffuse the issue just try to be patient and honest, if you can't process your emotions well then the strong ones you send can tire her out. I suggest taking up meditation if you are usually more emotionally charged. Or something else that keeps you calm, if that is the case. Hope this helped.