The expression was invented by [[NO U|Limp Bizkit]], a mediocre band of Wayward metalheads who mostly rap about [[Girlfriends]] and destroying shit.
[[woman|Women]] whom have failed at being [[man|men]] decided it was [[win|politically incorrect]] to put labels on people and so significant others were [[an hero|born]].
Whilst it is obvious that no "other" can be of any significance whatsoever, the [[fail|self-help]] book market found it to be a valuable [[tool]] for sales and soon sincere, direct expressions such as "[[whore|my spouse]]", "black person" and "the child I abducted last week" were replaced by "[[masturbation|my significant other]]."
The phrase is commonly used in [[Genital Herpes]] commercials to make [[your mom|women]] believe that having sores in their [[cunt|twats]] won't prevent them from [[asking for it|finding love]].
Usually [[vomit|barfed]] by [[hipsters]], homosexuals and bitter divorcées after a couple of [[faggotry|Martinis]], significant others are artificial extensions of the aforementioned douchebags, much like a [[trying too hard|prosthetic arm]] or [[Iphone|dildo]].