My wife of 20 years and I went out to dinner last night, and the conversation took a weird turn: she worries, a lot apparently, that besides the kids we have nothing in common. She wonders what this will mean once our youngest leaves for college in 8 years....

I was quite taken aback - I know we don't always have a perfect life, but I feel like if this was a concern, maybe it should have been brought up a long time ago? Like before we got married? Feeling confused and more than a little concerned. I don't have any of these concerns.

She did say that she talked to a co-worker about this and was told that "it's normal" - so I have to wonder, is it normal?

TL;DR: is it normal that a married couple has "nothing in common" except their kids?