The best thing you can do is to do your work properly and give
him less work-related problems so that he has time to go shop for a
new ring & be with his wife 
I think your boss is the type who kinda takes his marriage for
granted. It's very odd or foolish of him not to tell the wife
immediately upon losing the ring, instead leaving it for her to
find out. Upon loss of ring, instead of immediately searching for
it, he only did so after some time had passed. Also, a few months
after losing it and still no action on getting a replacement
ring?
There could be plenty of explanations for the above behavior, but
all I can say is damn shoddy work on his part. Wives are supposed
to be understanding but he has to make an effort. If he doesn't
change his attitude towards his marriage, there will be more
problems to come.