I'm 37 and I've been with my wife for 20yrs, but married for 8. We met less than a year out of high school, so I never had any other partners so not your usual situation. I personally feel about my wife the same way I did all those years ago, but I understand that's definitely not the norm. Do you have dreams about your wife any you splitting up? How do you feel in the dream? In mine I'm devastated and wake up in severe distress.
Also remember the grass is very rarely greener.
Also remember the grass is very rarely greener.