At dinner with friends last night - and one of my friends gave the quintessential Occam's Razor answer to why marriages fail. Occam's Razor...

"One should not increase, beyond what is necessary, the number of entities required to explain anything".

And the reason? Well... we live longer. In the past, life expectancy was what... about 35, 40 years? Get married at 19 and you only have between 16 to 21 years to slog it out. Today, in the developed world - average life expectancy is around 74. Get married at 28 and you may end up with your significant other for a whopping 46 years! :-)