Re: Is it true that...?
The general idea is that devoting yourself full-time to taking care of your children and your house is hardly time spent in leisure, so the idea that she doesn't "work" if she doesn't have a paying job is insulting.
A more neutral question is "What does your wife do?" because it allows answers that include being a full-time mom or a neurosurgeon.
If you said "Does your wife work" and she did not have a paying job, I hope he would answer something like "She sure does - taking care of me and our kids is a full-time job!" instead of "No, she's just a housewife."
I would suggest that you not ask a woman herself "Do you work?" Whether it's outside the home for a salary or as a full-time mom, she's working at something. (Unless, of course, she's one of those rich people with a nanny for the kids and a housekeeper for the house, but that's beyong my understanding. If you're able to be home all day, why wouldn't you want to be with your kids?)
PS - Welcome to Using English.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.