What is the first sign that a celebrity is heading for divorce?

Some people seem to think that when a celebrity is seen in public without a wedding ring, it is prima facie evidence that the marriage is on the rocks. This weekend, Jennifer Lopez was seen dressed to the nines at the premier of Brad Pitt’s movie, “the Curious Case of Benjamin Button.”
She was not wearing her wedding band. Nor was she with her husband. So everybody thinks the marriage is caput.
How many times did you go without your ring while you were still married? Did it mean the marriage was on the rocks? Why do we hold celebrities to this ring standard? It’s not even like you need to have a ring to get married in New York. At least, I don’t think so. All you need is a marriage certificate. The ring is optional. Isn’t it? So what is the big deal about wearing the ring? Except if you are a guy? In which case not wearing the ring could be a sign that you are up to ndg (no dam- good!)