I'm pretty upset about it and I plan on taking it to a jeweler to get fixed this weekend, but it just doesn't make sense to me. I've only had the ring 6 months. I've had other white gold rings that I've worn for years that are thinner and never did this.
My guess would be improper soldering, or they over polished after soldering which made that point weakest. You consistently put pressure on that area (driving) and it split. This sort of thing really shouldn't happen... especially since you have a thick non-pave band...
Sorry to hear that happened. My 5 month old solitaire ring split in May when they were mounting my new diamond in it. They said it was a flaw like an air bubble at that spot that made it weak. They replaced my ring and the new one has been fine.