My husband and I fly together probably 3 times a year at most so its part of the trip for us. I can completely understand if people fly a lot that its no great shakes but me I wouldn't be a happy cookie sat on my own.
On our first flight from Manchester to JFK we were split up but at check in they kindly bumped us into Business so we could sit together.
We both work full time and spend about 3 hours a day together so holidays are quite a treat for being together.
I also don't enjoy flying so I don't feel as bad holding/gripping my husband's hand as I would a stranger's on take off