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.
