Great read.  
"Live with a man 40 years, share his house, his meals, speak on every subject. Then tie him up and hold him over the volcano's edge.  And on that day, you will finally meet the man." --Shan Yu, via Firefly.  Amended, it might be "spend time with a person in all the times when you think they're unguarded, talk about everything.  Then get into a real crisis.  Then you'll know who it is."  You know, now, exactly who he is.  I'm not sure the girl married to the guy 12 years older does, not quite the same way.