Well... I've not been diagnosed as having SPD. And I have to admit much of what you wrote is beyond my poor ability to process.
But reading it I was thinking about my own situation. Although I am married, I am otherwise pretty-much entirely reclusive & have been for quite a few years now. And I spend a lot of time alone. One thing I have experienced over the years is that the more time I have spent alone, the more of a tendency I have had to veer off the "common highway" so to speak... in other words to develop & indulge in things that would likely seem peculiar, perhaps even bizarre, to the average person.
I think that day-to-day exposure to society in general tends to have a "molding" effect keeping us functioning more-or-less within the bounds of what society deems to be "normal" behavior. The more time we spend alone the more it is possible, perhaps even likely, we will stray off into our own little world.