A significant other whose status is not created by a agreed-upon relationship status but by how much time is spent with them. Could also be considered a behavioral significant other.
Combination of "statistically significant" and "significant other."
Since he spent twice as much time with Karen as with any of the other girls he was dating, his friends called Karen his statistically significant other.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)