As one faculty member who came here as part of a "package", I can attest to the difficulties of being seen as an individual.  Both my spouse and I have been offered the chair position during our time here, and both refused because of the potential problems.  We don't see the chair position as a promotion, rather a digression from our research/teaching/service path. Being a chair is a very difficult position, and it doesn't need to be made any harder by the presence of perceived conflict of interest in decision involving the spouse.  Remember that those decision can be not only promotions and raises, but difficult curriculum issues, teaching assignments, allocations of travel monies (you can probably think of two dozen other issues to be mentioned here.)