Part of it also depends on what one's expectations are, whether consciously or not. The generally accepted U.S. standard of living is that everyone will have electricity, indoor plumbing, a refrigerator, central heating and in most places, air conditioning. But as whitney noted people lived without these things for thousands of years.
Those who choose not to live that way (google "off the grid") are often perceived as, um, "touched in the head" or something. But it is a viable way to live since thousands do so.
In our case, we did live for about four months early in the marriage on one income when DW was between jobs, and after I retired we lived on just the retirement income for five years, but by then we had zero debt. At the moment I have a job and DW is ambivalent about whether she wants a job. This works for us, it might not for other people. As for me, I'd rather have a happy non-working wife than a stressed-out working wife. So if she gets a job and is happy with it, that's fine. If she decides that her, and therefore our, quality of life would suffer if she got a job then I'm fine with that outcome too. Now, it helps a LOT that she is in many ways more frugal than I am. Neither one of us places much importance on having the newest gizmos, cars, clothes, etc. because that stuff is just not important to us.
The point there is that is one of the couple is unhappy for long, and the other does nothing about it, the marriage will suffer in the long run.