So I read this story about 10-15 years ago and it would itself have been a bit older than that. I think it was in an anthology of short stories but I can quite remember. I think it was a longish short story.
The story was possibly set in Russia, and I think during a cold time of year. The main character was a lonely middle-aged man who created microscopic exhibits and displayed them in his own little curio museum. The exhibit I remember was a little mechanical exhibit of a camel passing through the eye of a needle. There were other exhibits but that's the one that was most prominently described I think.
I think I remember the book detailing his use of a single hair from a fly as a paintbrush.
The man fancied a girl who would often walk past his museum but she didn't notice/have any interest in him and also had a boyfriend.
He lures her in then shrinks her down and keeps her in a house he's made. The boyfriend tries to confront him, or maybe she asks for him, and the boyfriend gets shrunk down as well and lives with her in the tiny house.
Time passes and I'm pretty sure they have a baby, while the man has to look after them, shrinking down all the things they need like clothes and such and removing their rubbish. The man has no way to unshrink them and feels responsible for them. That's how the story ends.
Worth noting that the shrunk people are never on display in the museum and they are kept a secret from anyone else.
The general feeling of the book was quite dark and creepy.
Been trying to find this one for a while with no success. Many thanks if you can help me!