We present a simple variational scheme for calculating the binding energies and the lowest dipole optical transition energies of D-impurities in the middle of quantum wells at moderate and high magnetic fields. The objective was to make the model and the method as simple as possible but to be able to explain many of the experimental features observed. The simple form of the electronic wavefunctions used enables physical insight into the properties of the D- system in quantum wells. The scheme, based on the parabolic approximation for the conduction band, gives results compatible with those of more sophisticated approaches. A simple renormalization procedure makes the results compatible also with the experimental results for GaAs quantum wells for which band non-parabolicity proved to be important. The energies for the lowest dipole optical transitions were calculated for a broad range of magnetic fields and well widths.