  We examine an extension of the SM Higgs sector by a Higgs triplet taking into
consideration the Higgs-like particle discovery at the LHC with mass around 125
GeV. We evaluate the bounds on the scalar potential through the unitarity of
the scattering-matrix. Considering with and without $\Z_2$-symmetry on the
extra triplet, we derive constraints on the parameter space. We identify the
region of the parameter space that corresponds to the stability and
metastability of the electroweak vacuum. We also show that at large field
values the scalar potential of this model is suitable to explain inflation.
