Another long post, sorry. I'll split it into a few posts so it's less in-your-face. I want to try to give possible explanations from a ND perspective for a few things people have described. Hopefully it is helpful.
It is interesting to see NT people talking about having to process their interactions with their partners, having to interpret them differently, and react differently. That is what we ND people have to do constantly, with everyone.
It is like being a foreigner in this world. Every interaction has to be translated. It enters your brain, your brain thinks "Ok what does that mean?" It searches through its database, which has been built from a lifetime of experiences, to hopefully find the correct interpretation. Then you think of your response. But if you can't deliver your response in your native language (monotone, motionless, deadpan, direct), you have to translate it back first. Pick the correct words, choose the correct facial expression to display, choose the right body language. Then you present your response. All against a background of noise, anxiety and with the weight of expectation and responsibility on you.
To the posters here, it sounds like your partners skip the last part of the process. They don't translate their responses into NT language for you. But I can understand that because it is so mentally exhausting having to do that with everyone else, every time, every day, that we kind of don't want to have to do that at home with our family too. From your ND partner's perspective, you are their person. You are their mate. Their rock. They chose you. After all, they wouldn't be with you if they didn't love you. They want you to accept all this without them having to prove it in NT ways because that is difficult and unnatural for them to do. It actually feels less authentic to act in a certain way to "prove" feelings.