As a follow-up on the last post, I should note that there are of course university policies regarding people who are related. I am a few years ahead of my husband in seniority, but I have never been involved in any decisions or discussions involving his tenure or promotion. During both of his promotion processes, I left the conference room during discussions of his file, and never had private conversations with faculty colleagues about his promotions. I have recused myself on other occasions when decisions were made regarding my husband's research program or students. And we disagree often enough about department issues that we are not a "voting bloc".
In fact, we are so different in so many ways that the most common response is shocked surprise when students, faculty in other departments, and random other people find out that we are married. I am not sure exactly why it is so surprising that we are a couple, but whatever it is probably contributes to our not being viewed as a single entity and to our escaping some of the negative aspects that could come with being a couple in the same department.
There are some unique (=strange) situations that arise from our being in the same department. Example: last week, the department Chair had a talk with my husband about me -- the Chair expressed regret that he has been giving me stupid administrative tasks, and he wishes now that he had appointed me to a particular important position instead of the less-qualified guy he chose. Well, that's nice. I guess. He seems to have expected my husband to tell me the great news that I am respected more than I was, or at least more than I thought I was, but I would prefer to hear this directly from the Chair. But, if he didn't have this "indirect spousal communication mechanism" for conveying the information to me, perhaps I wouldn't even know it at all.
Some colleagues told me a few years ago that they weren't comfortable with my ever having a departmental leadership position because my spouse is in the same department. These same colleagues enthusiastically supported a male colleague whose wife is a faculty member in the department, somewhat undermining their ethical objections about me, but to no practical effect. No one was interested in discussing whether this meant that we as a department think that men can be more fair in nepotism situations than women.
I am not claiming that having couples in the same department is easy or even desirable, but it's an inevitable situation, and there are ways to make it work.
6 months ago