QUOTE(fwaguy @ Feb 28 2008, 12:25 PM)

I can't see why... you need to demonstrate 3 years of marriage to a USC.... I am not aware of any requirement to demosntrate conjugal living arrangements
There are definitely requirements to live together, per INA 319(a).
From
The USCIS interpretations 319.1The requirement that the petitioner live in marital union with the citizen spouse during the three-year period should be given a reasonably strict construction in order that it may lead to accomplishment of the objective of having the noncitizen spouse absorb basic concepts of citizenship through close association with the citizen spouse.
...
It has been held, however, that the residence in marital union, or at least a substantial portion thereof, must be in the United States, with the citizen spouse.
As YuAndDan pointed out, there's other language that says that a temporary separation for reasons outside the control of the couple or for essential business demands does NOT preclude naturalization, so I think aying may well be in the clear, but that does NOT mean there are no requirements whatsoever to live together in the same household.
Any time you live in separate households, you're starting to get into a grey area. I'm not sure if avoiding a one hour commute would constitute "true economic need" as the text quoted by YuAndDan says.
I'm certainly not qualified to weigh all the factors and give an answer here. I could imagine it being argued either way.