I had never heard of this or seen it before, but supposedly it is fairly common. https://en.wikipedia.org/wiki/Work_spouse
Yep. I'm on work wife #3.
#1 was promoted and is now my boss. We're still friends.
#2 married for real and moved to another city. We're still very close.
#3 is far less intense a relationship than the first two. Very cordial and friendly. We're cubemates and get along exceptionally well.
Makes the work day less dreary.