  We study spatial and temporal solitons in the $\mathcal{PT}$ symmetric
coupler with gain in one waveguide and loss in the other. Stability properties
of the high- and low-frequency solitons are found to be completely determined
by a single combination of the soliton's amplitude and the gain/loss
coefficient of the waveguides. The unstable perturbations of the high-frequency
soliton break the symmetry between its active and lossy components which
results in a blowup of the soliton or a formation of a long-lived breather
state. The unstable perturbations of the low-frequency soliton separate its two
components in space blocking the power drainage of the active component and
cutting the power supply to the lossy one. Eventually this also leads to the
blowup or breathing.
