The Groom's Ex Showed Up as Someone's Plus One

My friend was getting married, and the whole thing was lovely right up until the reception, when we all learned who a certain cousin had brought as his plus one.

The cousin, a well-meaning but oblivious man, had recently started seeing a woman he had met online. He brought her to the wedding as his date. What he did not know, and what became clear to the rest of us with slow horror, was that his new girlfriend was the groom's ex, the serious ex, the one from before, who had apparently recognized whose wedding this was the moment the invitation was mentioned and said nothing, and come anyway.

She was quiet through the ceremony. She saved it for the reception. After a few glasses of wine she began toasting, loudly, to no one in particular, to "what could have been." She cornered guests to tell them she had dated the groom for three years and that "some people just settle." She asked the DJ to play a specific song that, we later learned, had been "their" song.