Instead of answering her as ...

Instead of answering her as soon as he saw her hair grow electric, her face more vivid, her eyes like lightning, her body restless and jerky like a racehorse’s, he retired behind this wall of objective understanding, this gentle testing and acceptance of her, just as one watches an animal in the zoo and smiles at his antics, but is not drawn into this mood. It was this which left Lilith in a state of isolation - indeed, like a wild animal in an absolute desert.
Instead of answering her as soon as he saw her hair grow electric, her face more vivid, her eyes like lightning, her body restless and jerky like a racehorse’s, he retired behind this wall of objective understanding, this gentle testing and acceptance of her, just as one watches an animal in the zoo and smiles at his antics, but is not drawn into this mood. It was this which left Lilith in a state of isolation - indeed, like a wild animal in an absolute desert.

Quotes from the same author

Age does not protect you from love. But love, to some extent, protects you from age.
The dream was always running ahead of me. To catch up, to live for a moment in unison with it, that was the miracle.
The possession of knowledge does not kill the sense of wonder and mystery. There is always more mystery.
The personal life deeply lived always expands into truths beyond itself.
Dreams pass into the reality of action. From the actions stems the dream again; and this interdependence produces the highest form of living.