Here it is. It took a while to track down. From A Buyer's Market by Anthony Powell.
The lack of demur on her part seemed quite in accordance with the almost somnambulistic force that had brought me into that place, and also with the torpid, dreamlike atmosphere of the afternoon. At least such protests as she put forward were of so formal and artificial an order that they increased, rather than diminished, the impression that a long-established rite was to be enacted, among Staffordshire figures and papier-mache trays, with the compelling, detached formality of nightmare. . . . I was conscious of Gypsy changing her individuality, though at the same time retaining her familiar form; this illusion almost conveying the extraordinary impression that there were really three of us--perhaps even four, because I was aware that alteration had taken place within myself, too--of whom the pair of active participants had been, as it were, projected from out of our normally unrelated selves.
In spite of the apparently irresistible nature of the circumstances, when regarded through the larger perspectives that seemed, on reflection, to prevail--that is to say of a general subordination to an intricate design of cause and effect--I could not help admitting, in due course, the awareness of a sense of inadequacy. There was no specific suggestion that anything had, as it might be said, "gone wrong"; it was merely that any wish to remain any longer present in those surroundings had suddenly and violently decreased, if not disappeared entirely. This feeling was, in its way, a shock. Gypsy, for her part, appeared far less impressed than myself by consciousness of anything, even relatively momentous, having occurred. In fact, after the brief interval of extreme animation, her subsequent indifference, which might almost have been called torpid, was, so it seemed to me, remarkable.
... and a little later on all you can think about is a bratwurst and an autobahn ... 
