Sineã®mine wrote...
It's hard to say whether it is "true" or not. There are aspects of the truth in it, and yet, at that same time, you want to be very careful not to stereotype.
One thing that should be noted, however, as westerners, is one particular aspect of culture. Thanks to how the language itself works, you are supposed to humble your own stuff to people you respect (謙è²èªž). Language influences culture, and as a result you see lots of couples in Japan that will regularly bad mouth their own spouse to other people every chance they get. You hear lots about "useless" husbands and "worthless" wives.
This stands in stark contrast to our usual way of doing things, namely bragging about every aspect of our life that we can conceivably get away with bragging about, to the point of even lying about how good our lives are to feel better about ourselves. This could be part of the reason why the impression develops. Things seem pretty bad when if you ever ask anyone, all they have to say about their spouse are the worst, most negative things.
That isn't the whole of it, but one aspect.
I use to really want to visit and possibly live in Japan. I did a bunch of research which actually convinced me against it because of the type of person I am. What I read confirmed this sort of thing. They didn't necessarily believe their spouse was "worthless" or "useless", but it was an act of humility. Their spouse could be amazing, but instead of bragging about it they downplay it. As far as I've read humility is an extremely important aspect of Japanese culture. If this is old or wrong I implore you to point it out.
As a side note something else to keep in mind is "politeness" in one country is different then in another. In Japan it is perfectly fine to slurp your ramen versus in many western cultures where that is impolite. Also in Japan it in not necessarily impolite for a guy to let the door close in front of their date's face because they didn't hold it open. I can't remember the exact reason behind why it isn't impolite...