  We consider singlet extensions of the standard model, both in the fermion and
the scalar sector, to account for the generation of neutrino mass at the TeV
scale and the existence of dark matter respectively. For the neutrino sector we
consider models with extra singlet fermions which can generate neutrino mass
via the so called inverse or linear seesaw mechanism whereas a singlet scalar
is introduced as the candidate for dark matter. We show that although these two
sectors are disconnected at low energy, the coupling constants of both the
sectors get correlated at high energy scale by the constraints coming from the
perturbativity and stability/metastability of the electroweak vacuum. The
singlet fermions try to destabilize the electroweak vacuum while the singlet
scalar aids the stability. As an upshot, the electroweak vacuum may attain
absolute stability even upto the Planck scale for suitable values of the
parameters. We delineate the parameter space for the singlet fermion and the
scalar couplings for which the electroweak vacuum remains stable/metastable and
at the same time giving the correct relic density and neutrino masses and
mixing angles as observed.
