I can empathize, Squggy. I crave stability, but I am constantly looking for new stimulation. When I find something new, I obsess, until I loose interest. Then I fall into a dark down period, until I find something new to obsess on. It's an up and down emotional cycle completely of my own creation.
I think that my children have become a bit of an anchor, in a way. Because of them, I still have the same job I had 8 years ago, and we have lived in the same apartment for 5. But other things...
Relationships and interests....those burn bright for a time, then pale, and I look for something new and shiny.
None of this is nearly to the extent you describe, but as I said, I can empathize. If you ever find a cure, lemme know, OK?