How long have you known your oldest (time wise) friend?There's exceptions to everything in life.
Most people grow apart though. A lot choose to stay together anyway.
Believe me I understand about growing together, but at the end of the day we are all individuals with our own interests.
If you can have a best friend for 30 years and still keep common interests, surely you can do the same with a wife. You don't stay friends with someone solely based on common interests and "growing apart" is only a matter of perspective.