Abstract: Smart jewelry faces challenges in split interaction due to its dual-domain separation, primarily manifesting as "cognitive disconnect "and "trust erosion". To systematically diagnose these issues and propose effective solutions, this study proposes the "Wearable Dual-Domain Action Cycle Model" based on Norman's action model, employing longitudinal mixed-methods experiments to collect multimodal user data and conduct qualitative interviews for analysis. Results indicate that the navigation gap in the digital domain increases cognitive load for novice users; the haptic-digital translation gap, hardware aging, and data inaccuracies reduce both usability ratings and trust levels among experienced users, while physical material degradation and digital feedback discontinuities are key contributors to the "trust crisis" in smart jewelry. Finally, the study recommends "physical reconstruction" and "honest design" strategies—replacing resin with single-crystal synthetic sapphire to ensure signal fidelity and introducing data confidence visualization mechanisms in the digital domain to enhance the emotional durability of smart jewelry.