I think Alexithymia is the best "description" I've yet found, and I rated rather high on the test, but a lot of the questions didn't really apply to me.
For the longest time, I thought I was borderline sociopathic, or some form of autistic, but neither of those really fits.
I am very good at sympathizing with others, in fact I would go so far as to say I can empathize with them. However my version of this might be very different from how a "normal" person would. For me, I don't feel intensely for them so much as deeply understand how and why they feel a certain way. It's very clinical, but also I still feel "compassionately" for them on some level, and I've had many, many people tell me that I understand them better than anyone else has but I often think that this is more in the sense of how a psychologist might understand someone better than their best friend. I'm good enough at it this "sympathic/empathetic" analysis that I commonly attract people to me that confide in me with their deepest darkest personal and emotional struggles and seem to derive insight from my responses. I find it very easy to "read" people in general, and to the extent that this is testable, I'm quite accurate. All of that would seem to indicate that I am not Autistic or possibly Alexithymic.
Now for how I think I fit the definition. My mind is rigidly, logically ordered. I almost never think in terms of emotion or how something makes me feel. I think in terms of facts and logic. This doesn't mean that I am unbiased, but to the best of my ability my thoughts are centered on reality as I know it. 95% of my thoughts do not have any emotions attached to them. In relationships it is common for the other person to get angry at me for "trying to fix the problem" instead of just "listening to them", though they rarely or never say that my responses are inaccurate. I do not normally feel any emotions about anything unless it is an extremely intense emotion. Even then, I feel that based on many conversations and observations of others, that these emotions are very muted. Though I am heavily introverted and also suffer from anxiety about spending time in large groups or loud places, I do enjoy spending time with people I am friends with. I am generally a highly ethical and moral person, and one of the few ways I derive significant pleasure is on making other people's lives demonstrably better, but I don't get much satisfaction from improving my own life. In fact I have been told by many people that I trust that I am one of the "best" most "moral" people they know. This behavior extends to when I do not feel that there would be any bad behavior and when I would personally benefit from doing something I find ethically or morally wrong. I am an atheist, so I do not even have the excuse of some sort of eternal retribution for bad behavior. Hence, I do not think that sociopathy describes me. My emotional bandwidth seem very limited compared to most people. My Ex-wife, who was diagnosed and obviously Aspie would regularly mood swing in both directions far more than I could ever achieve. I didn't even realize how little emotion I normally felt until I recently started taking a supplement called Phenibut that suddenly made a night-and-day difference. Suddenly I felt "micro-emotions" attached to most thoughts I had, and I started feeling way more empathetic about things that didn't affect me personally. These all felt like very positive changes, and I felt extremely "dead inside" for the last 8-10 years of my life. Ultimately it isn't really important to be able to name my condition, but it would be nice to know. To the extent that my mental lack of emotion effects my life, I think it has been very positive in terms of my ability to accomplish positive objectives. I can typically shove any emotions I do feel into a box and push through adversity to achieve a calculated objective. Many people have told me that my executive function far exceeds average. The negative impact was only recently revealed to me via the previously mentioned mental shift via medication. It felt like the difference between never seeing color, and suddenly being able to see color. I don't think I was always this way. I think the shift occurred somewhere in late high school or college. My memory of childhood which is backed up by friends and family was that I was a highly emotional and empathic child with a hyperactive imagination. I remember commonly crying because I felt bad for a friend or when a pet would die, even when fellow playmates were long over it or would make fun of me. I also had/have a bit of a hero complex. Even though I was a small child I would often jump into fights with much larger children who were bullying others. In spite of that, I don't think I have a particularly narcissistic world view. I've never been particularly popular or well liked, and that has never been a big concern of mine, though I do have a pretty positive self image.
I would appreciate any insight that others might be able to share.
You could still be, very mildly, autistic. But in the same way as you I can accurately read and interpret the actions of other people... they also find it easy to confide in me, but! I can't feel sympathy or empathy. I just understand that their reasons are... Well. Reasonable?