We argue that the $d_{x^2-y^2}$-wave superconductor is marginally stable inthe presence of external perturbations. Subjected to the external perturbationsby magnetic impurities, it develops a secondary component of the gap, complex$d_{xy}$, to maximize the coupling to impurities and lower the total energy.The secondary $d_{xy}$ component exists at high temperatures and produces thefull gap $\sim 20 K$ in the single particle spectrum around each impurity,apart from impurity induced broadening. At low temperatures the phase orderingtransition into global $ d_{x^2-y^2} + i d_{xy}$ state occurs.
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