What is the difference between Girlfriend/Boyfriend and Significant Other?

[Anonymous]

I have never been referred to as her "Boyfriend", only as her Significant Other.

I don't know if that's supposed to be a meaningful difference because my past relationships I've always been called their Boyfriend.

[Avicenna]

Significant other could also be a spouse, so it's a broader term in that sense.

[Anonymous]

I guess it could relate to a spouse or domestic partner if they are the same sex or maybe they have been together a long time

[TacosRAwesome]

Nothing but you don't want to specify their gender or you're a bit older.