I say this marriage is doomed.
If you insist on altering classic usage, what happens to the phrase “Don’t get your undies in a bunch”? Is it then “Don’t get your undy in a bunch”? That’s pathetic.
I require a pair of boxers for my pair of testicles. 
How many underwears are you wearing?
One underwear? Just an underwear isn’t enough! You need a pair of underwear.
But if someone asked for a pair of underwear, I would immediately assume one article of clothing.
How many underwear do I have?
How many pairs of underwear do I have?
I know which sounds right to my ear.
Interesting observation.
Weird how? The earrings, unlike your previous examples, are TWO (count 'em, two!) SEPARATE items. On what planet would it be weird to call them a pair?
…and your pair of cheeks.
Thanks for posting this. Interesting read. English is my second language and I love to learn about the origins of words…whether they are rational or not, it’s most often entertaining.
I can’t speak for indian, but for me the odd word in the sentence isn’t “pair”, but “underwear”.
“Pair of pants” would be fine, or “underpants”, “panties”, “shorts”, “briefs” – anything of that sort.
“Underwear” is, for me, too broad and non-specific a category to go with the word “pair”, since it encompasses undershirts, bras, slips, petticoats, garter belts etc, none of which are generally thought of as a pair.
If I were in the position of Mamavalveeta03’s husband, I would have asked if I had “a clean pair of (under)pants” or “any clean underwear” (or “some clean underwear”).
In Spanish it can be single, or a pair, or plural. Este pantalón refers to these trousers, *este par de pantalones *refers to the same trousers, estos pantalones can refer to those same trousers again or to several pairs. You usually can figure out which either from context or because there is more information provided. Pantyhose is paired or plural, panties can be singular or plural but not paired, bras are singular, men’s shorts-briefs-etc are plural or paired.
Same in Catalan, not surprisingly (the majority of Catalan speakers are bilingual with Spanish; not only is there a common origin but a lot of cross-pollination between the two languages).
Not weird that earrings are counted as a pair, weird that some things are pairs and some things aren’t.
Pretentiousness. Or one-legged models.
And who the heck is ‘Ralph Loraine’? You mean that Lifshitz guy from the Bronx?
Bah! It’s cleaner, more consistent usage minimizing qualifiers that don’t actually say anything about the product. Seeing as how one-legged pants aren’t marketed, it’s superfluous to refer to a pant as a pair. You should expect a two-legged pant.
And what about underpants? No pair present.
Do you refer to your legs as a pair? No. They come in pairs. No need to point that out in language.
OP: Have you never heard it called a pair of underwear or a pair of pants? Really? I assumed that was the most common usage.
To me, it sounds like you’re nitpicking. If you’ve really never heard that usage before, you’re the first person I’ve ever encountered who (presumably) has English as a first language and has never heard the term “pair of underwear.”
Oh, and on preview: your husband is right. One item is a pair of underwear. No, it doesn’t necessarily make sense, but neither do a lot of things in the English language.
Well, the first option would be rephrased as “How much underwear do I have?” I could see myself asking that question.
In this case, why has no one in this thread commented on the oddity that brassiere is singular…
This is usage retained from several centuries past when men’s nether garments did come in pairs. The Robin Hood-style “men in tights” were wearing what were essentially a pair of hip-length stockings laced to the bottom of their shirts or to a belt. People kept on referring to them as a “pair” even after the separate legs were merged into a single garment.
An easy way to sort out this issue is to grab his pair of balls, place them inside his pair of pants, check your pair of ti* and then say sorry for your misunderstanding 
nm
Arise, Oh Zombie Gitch!