Amy is growing tired and wary of Desi, who is constantly trying to remind her how safe and loved she is—though she doesn’t feel safe and loved, as she has become his prisoner. She has no way to leave the house, and has begun to fear that Desi’s mother, Jacqueline—who has always hated Amy, and has always been onto her lies—will come up to the lake house and discover her.
Amy has made a mistake in giving herself over to Desi. She underestimated his rabid adoration of her, and has essentially become his captive. The lies Amy has sown are catching up with her, and the truth is becoming stranger than any fiction she could spin.
Desi comes daily to bring Amy lunch—small portions of fruit and seafood designed to force her to lose the weight she’s gained. Desi has also bought Amy hair dye and all but forced her to dye her hair back to its normal blonde. Desi always couches his demands in a desire for Amy to feel like her best self, so she can’t say anything to push back against him. As the days go by, Desi begins making “threat[s] disguised as concern,” telling Amy that if he ever comes by and finds her gone, he’d go right to the police—for fear that Nick had kidnapped her back. Amy realizes she has underestimated Desi, and has lost control of the situation entirely.
Desi is clearly trying to mold Amy into the woman of his dreams based on the narrative he’s told himself over the years about who Amy is, and about what being with her would be like. By being his prisoner, Amy is getting a taste of her own medicine on all fronts.