Forever Ring, Forever problems!!

My husband bought my white gold forever diamond ring in October 2010, I only wore it on our wedding day in November 2011 (to prevent the ring tan on my finger). Last year we had to replace one of the diamonds in the forever word after routine cleaning/maintenance and now another diamond has fallen out. I have looked after my ring, made sure it was rodiumed once a year and worn only when needed. It has only been about 4 years since I have had my ring and it now is missing yet another diamond!! Its upsetting as you pay so much for the ring only for it not to last anywhere near forever!! It is just upsetting the quality of the rings sterns is selling!! How much more am I going to have to pay now to repair this!! Very disappointed!