It was that way in the US for a very long time. Sometime in the last couple decades a new trend arose to wear both the engagement ring and a wedding band together. The logic being you spent 4-5 figures on beautiful jewelry, so it's silly to only wear it during the engagement. (Whether it's silly to spend that much in the first place is another argument.) I don't know if they are in fashion currently, but many jewelers began selling engagement rings with a paired wedding band that is designed to match perfectly and be fused with the engagement ring after the wedding.
> The logic being you spent 4-5 figures on beautiful jewelry
Good lord, people do this? People spend ten thousand dollars on a ring? Fuck. When we got engaged, we shopped together and I bought her a black opal ring. Diamond was never on the menu, so I never even looked at their prices. I knew diamonds were expensive, but I had no idea the extent to which people were getting suckered.
There was a big ad campaign from the diamond cartel to make everyone believe that 3 months of (gross) salary was the standard amount to pay for an engagement ring. That means if you only make $36K/year, you still shell out $9K for a ring. I don't know how many bought into it, but it likely did raise the average amount paid by anchoring the price so high. "That's crazy! Maybe half that..."
> Good lord, people do this? People spend ten thousand dollars on a ring?
No, of course not - why would you think that? Those 'high priced' rings are like the wax fruit in a greengrocer, or plastic lobsters at the fishmongers - just there for show...!
Back in the real world, people can actually spend hundreds of thousands, even millions, on jewelry.
It's pretty much always been the case that a married woman would wear both her engagement and wedding ring? There's even long-standing etiquette about the order in which they should be placed on the finger - engagement first, I believe? It certainly isn't something new since the 1990s.