I went easy on you because I wanted to model going easy on you for YOU!

What you are describing with the blunted affect probably is caused by your PD (schizotypal). I know very well what you are talking about - I have seen such men. for some reason I have not seen such women - go figure. My first thought on this is the following: try paying attention to one thing (to avoid being distracted and overwhelmed) - distance between two conversation partners. Observe how other people talk and try to tease out what the comfortable distance is as other people talk. You seem very analytical, so just imagine that you are recording data into your brain each time you see two people talk, and then run some data analysis in your head to determine what the typical distance is. Of course, this does not include fights or kissing - just neutral conversations.

If you do that, keep yourself at that comfortable distance in your own conversations, you would avoid the awkwardness of having a "wide stare" while being too close to a person you are listening too. As for nodding, stop nodding continuously and in general stop nodding for now, and just listen to the cadence of human speech. Nodding meaningfully is for the most part just a matter of getting the rhythm right. Imagine an orchestra playing and the drummer does not drum continuously, nor does he drum randomly - he does the drumming at peak moments in the flow of the music played by the orchestra. So in human speech, people either nod fairly continuously but rhythmically (so nodding continuously without making people thing that you are a fraud or are messed up IS possible, and such nodding is a habit of some people - women more often than men, in my experience, but you need to be in sync with the rhythm of what is being said, so that takes us back to the homework of attentive listening), or, they nod at crescendo moments (to discern when they happen, again, you need to listen attentively).

I know it is a lot.

Let me just add that one man whom I know with this blunted affect is a successful professional who recently got married and is quite happy in both his personal and work life.