I love that word "entanglement" as a description of Judy and Dexter's relationship. It's perfect for them: Judy keeps drawing Dexter in with her charms and beauty, filling his head with thoughts of marrying her, and then pushing him away while she gets involved with other men. Helplessly lovesick, Dexter willingly lets her do all this. And the intensity of their on-again, off-again liaison is beautifully conveyed by Fitzgerald's use of imagery. Let's check out some examples.
1. "It was a mood of intense appreciation, a sense that, for once, he was magnificently attune to life and that everything about him was radiating a brightness and a glamour he might never know again."
Here's an example of imagery so vibrating with intensity that it's not even focused on any particular object. Dexter imagines himself as surrounded by "brightness" and "glamour" as Judy approaches him from the water. His entire world is humming with light and beauty because she's in it.
2. "Early in their acquaintance it had seemed for a while that there was a deep and spontaneous mutual attraction that first August, for example--three days of long evenings on her dusky veranda, of strange wan kisses through the late afternoon, in shadowy alcoves or behind the protecting trellises of the garden arbors, of mornings when she was fresh as a dream and almost shy at meeting him in the clarity of the rising day."
The intensity of their relationship here, in its early stages, is communicated through images of darkness, shadows, and light. The image of the "protecting trellises," in particular, emphasizes the passionate secrecy of their affair.
3. "Judy Jones, a slender enamelled doll in cloth of gold: gold in a band at her head, gold in two slipper points at her dress's hem. The fragile glow of her face seemed to blossom as she smiled at him. A breeze of warmth and light blew through the room."
This is how Judy waltzes back into Dexter's life just when he'd made up his mind to forget her and marry Irene. Imagery of Judy as not even human but a perfect "doll," dressed in heavenly "gold," almost literally an angel wearing a golden halo, and emanating "warmth and light" from her smile--all of this is classic material from Fitzgerald, who likes to overwhelm us with this kind of passionate imagery.
4. "The strong walls, the steel of the girders, the breadth and beam and pomp of [the mansion] were there only to bring out the contrast with the young beauty beside him. It was sturdy to accentuate her slightness--as if to show what a breeze could be generated by a butterfly's wing."
Here, the imagery of the strong, masculine mansion is juxtaposed with Judy's graceful, slender figure, a comparison which reveals the depth of Dexter's obsession with her. That is, he is so focused on her that he perceives everything else in terms of her.
5. "The gates were closed, the sun was gone down, and there was no beauty but the gray beauty of steel that withstands all time."
This imagery plays out in Dexter's mind when he realizes that Judy's desirability as a creature of eternal beauty was an illusion. The images of a closed gate, darkness, and cold steel combine to convey the crushing depth of Dexter's sense of loss. It's not just that he's losing Judy forever, but that he's losing his entire conception of what she was.