The character in this story is an idiot, let's just get that out there. She is born into "poverty" but she isn't really poor, she just isn't wealthy. She has a maid, for heaven's sake. However, she dreams of diamonds and silks and thinks she's made for better things. When her poor husband comes home with an invitation to a fancy party she throws a tantrum and insists on a new dress. He unselfishly gives her everything he has saved for his own pleasure so she can have the dress. Then she frets because she won't have any nice jewels to wear. He suggests she borrow some from her rich friend and she does and they go to the party and she's the belle of the ball. After the party, however, she realizes she's lost the necklace. Instead of coming clean to her friend, she has her husband mortgage his life and soul to buy a replacement. They then spend the next ten years of life in ruinous debt and real poverty.
I had no sympathy for the woman in this story. I thought she was shallow, frivolous, and ridiculous. On the other hand, my heart went out to her poor husband who didn't deserve the ruin his wife brought on him and yet he never complains or abandons her. This is one of those stories where you are screaming at the characters to just talk out their problems instead of ruining their lives with desperate acts. It's a good story and I can see why it's a classic, but I also think it's a bit heavy-handed. The theme, as far as I can tell, by the way, is that life is too short to waste on material goods and you should be satisfied with what you've got and not go chasing after riches. Or maybe it's just don't reach above your station. Then again, you could say it's a cautionary tale about coming clean and not trying to hide your mistakes. Whatever, I'm terrible at finding the themes in a story. All I know is that, if I had been that idiot's husband, she would have been my ex-wife as fast as I could manage it. The poor guy deserved better.