My personal opinion is that if you think you need a prenup, then you probably need to reconsider getting married in the first place, because there's a serious trust issue present.
I'm not married, but my current GF is marriage material ... we'd likely be cohabiting if not for the minor little annoyance that my job is in NC and her grad school is in Houston! She loves to travel, and is understanding of my career choice ... though she's not completely thrilled with the schedule (I don't think ANY pilot's spouse ever is). Her only stipulation is that she wants to live in Texas ... not a big deal because I really want to move back there too, and I'm willing to commute to do it, although a Texas-based corporate job or an airline with TX domiciles would be preferable to a lifetime of commuting! Plus, not paying state income tax is a nice bonus, especially if we're talking regional FO wages.
A buddy of mine who is an ACA captain once told me, "Most pilots wind up living wherever HER family lives." In his case, truer words were never spoken ... he moved to rural Alabama at his SO's request!
To me, I think having a person who is independent and can handle the household while you're gone is important. Ideally s/he would have a portable career ... my GF is in social services, and (other than licensing/certification hassles) there is a demand for people in that field everywhere. That way, if a move (or multiple moves) are in the cards, s/he won't be toast job-wise if you get transferred from Nome to Key West. A high trust factor is a must, given that opportunity (in the form of hotel rooms in strange cities, etc.) for infidelity is certainly present.
FL270