SFG
Nabokov definitely believed very much in detail as a crucial element of excellent writing. The sort of detail that you are referring to.
I've seen that belief of his mentioned in several places that I can't put my finger on. That he was able to create such vivid and detailed scenes in his mind evidently took a fair amount of thinking about them, and also actual careful research observing and taking notes about actual school girls on buses and in playgrounds, as well as having a number of conversations with their family friends' daughter whenever they came to visit, (all mentioned in Boyd and/or
Vera). He was also, not so incidentally, an avid reader of popular magazines and newspapers [read "non-intellectual" including "trash"] to keep up with details of pop culture. He saved matchbooks from the motels they stopped at on their butterfly expeditions, and I imagine he probably looked at and took notice of everything that passed before his eyes. If he read milk cartons, as potential grist for his eventual mill, it would not surprise me in the least. He was devoted to the craft of writing and didn't rely only on genius and flashes of inspiration alone. And he produced an enormous output as a result.
No credible hint that he himself was ever the way you suggest has ever surfaced, although the thought has always come up, and always been denied completely by people who have known him directly.
Now, if you want to say "womanizing,"
there's a whole 'nother story. (see
Vera, at the least).
Do tight rope walkers have hidden wires that are holding them up there doing things that none of us can do? I think not. Certainly not necessarily.
In their case it is practice, practice, practice. For Nabokov it was imagine, imagine, imagine I would say.
How do you prove something never happened? Never sufficiently well enough to satisfy everyone, is all I can say.
Meanwhile, please try to enjoy the parts that don't turn you hair on end,
There are definitely some of those too,
Peder