Long-Horizon Dyadic Commitment, Concentrated Coordination Load, and Conditional Fragility

This Version 1.0 preprint develops a theorem-driven structural account of delayed coupling, inhibited formalisation, and elevated relationship dissolution under conditions of diminished orientation, concentrated private coordination load, heightened uncertainty, and insufficient buffering. Rather than treating declining marriage rates, delayed partnering, non-formation, or dissolution primarily as direct expressions of preference change, moral decline, gender conflict, or isolated legal and economic factors, the paper reframes these outcomes as downstream manifestations of altered feasibility conditions for long-horizon dyadic commitment. The argument begins from a minimal set of structural commitments: long-horizon dyadic commitment depends on a minimally coherent feasibility relation among orientation, predictability, buffering, perceived solvability, and manageable coordination load; hyper-individualised contexts increasingly concentrate responsibility and regulation inside the dyad or household; and when perceived carryability falls below threshold, delayed coupling, inhibited formalisation, conditional brittleness, and exit become structurally intelligible outcomes. From these commitments, the paper derives a theorem architecture linking formation thresholds, formalisation inhibition, selective retention, conditional brittleness, threshold dissolution, and exit as a stabilising response. The dyadic-viability family is developed in full, with observable implications, negative implications, temporal-ordering expectations, challenge conditions, boundary conditions, and downstream empirical instantiation logic. The contribution is structural and diagnostic rather than moral, clinical, or policy-prescriptive. The paper does not argue that contemporary people value commitment less, that autonomy or gender equality are causal problems, or that all dissolution is pathological. Instead, it specifies what follows when long-horizon dyadic commitment must be carried under weakened scripts, intensified private coordination burden, heightened uncertainty, and insufficient distributed support. Within the wider research programme, the article functions as a support and bridge theorem text connecting structural viability, social burden transfer, family formation, dyadic feasibility, and the distinction between visible relational outcomes and underlying load-distribution mechanisms.