Significant Other?

Ok so I'm off to a wedding tonight but am going as my friend's 'guest'. Having just split with her partner, does this make me her significant other? If so what on earth does one wear? I've been called many things in my lifetime but significant other is not one of them....Suggestions on the back of a fag packet please....

Social Event likelihood of snoggage - For reasons I can't divulge probably a huge zero unless I can get away with not being seen by the assembled guests.

*Still titling