Dr Rob Dobren­ski of Shrink Talk has an absolutely fan­tas­tic post on rea­sons why mar­riages fail. These are the seven he felt wor­thy of note:

  1. Mar­riage requires com­pat­i­bil­ity not just at the point of say­ing ‘I do,’ but across the entire life span.
  2. Assum­ing that mar­riage implies monogamy, the insti­tu­tion itself is coun­ter­in­tu­itive to biology.
  3. There is far too much empha­sis on ‘wed­dings’ as opposed to ‘marriages.’
  4. Many cou­ples do not know how to fight fairly.
  5. Mar­riages [don’t] solve problems.
  6. Peo­ple set­tle for less than what they want.
  7. Cou­ples assume they are immune to rea­sons 1–6 and believe that hard work isn’t part of the deal. They think that love, sex, chil­dren or some com­bi­na­tion thereof will be enough.

On the topic of mar­riage I found this reca­pit­u­la­tion of John Molloy’s Why Men Marry Some Women And Not Oth­ers inter­est­ing (and a lit­tle ridiculous).