My experience has also told me the often quoted 50% number was bogus. My guess was always that those who divorce and remarry over and over skew the numbers, but it turned out the numbers were completely bogus to begin with.
In my experience, couples I know who have divorced experienced one of two scenarios:
a) The man was not willing to keep to his marriage vows and engaged in adulterous behavior
or
b) The woman bought into a bunch of Oprah-esque pop psych philosophies that she had a “right” to be absolutely happy. Something that is utterly unattainable on this Earth, and which no man is able to provide.