its a word the loveable asshole will kirby made up.
also the word is copy righted so will can say it you cant...cause he'll sue your ass.
Once the run is over so is the romance.
The term originated in the theater and moved to movies and scripted television and then reality television.
The term has now moved to the populace to discribe any contrived romance.
Dude 2: It's just a showmance, Cicely is just dating Anthony just to make Edgar jealous.
Dude 1: I didn't know Anthony and Cicely were dating.
Dude 2: They're not. It's just a showmance, Anthony is gay.
Showmances do, however, develop between two co-stars playing roles in which they are in no way romantically linked, however due to long hours on set and often odd or isolated locales, a couple may develop some sort of relationship to bide their time or otherwise entertain themselves.
An actor or actress may mistake scripted passion or chemistry on screen, for a real life romance off-set. Showmances typically end after the filming has ended.
(see "House: MD" co-stars; Jennifer Morrison and Jesse Spencer; now engaged, they started their romance around the time it was written into the show)
Dude, I'll intro you to the show-mance tonight. She's a real douche.