In hindsight, he should've taken a few moments at the very least to see who was in attendance at this ball before dragging River out of the TARDIS. He really only had himself to blame for this turn of events.
And if he knew Jack, the captain would eventually ask him to dance as well. And he would accept, if he knew himself (which he rather prided himself on). But given that Jack flirted with anything with a pulse (and probably some androids as well) he knew that River would get along with him from the moment they met.
Precisely the reason he never wanted them to meet.
Ever.
Tipping his champagne flute back and forth on the table with what was assuredly a bored look on his face, he watched his wife and friend whirl effortlessly across the dance floor, their chests touching a little more than he was comfortable with. Which was to say, at all.
If there was anything to be said about Captain Jack Harkness, it was that he had some nerve.
A/N: The inspiration for this comes from Miserable At Best by Mayday Parade, but only the line "I'll bet he'll get the nerve to cross the floor and ask my girl to dance." The rest of the song is actually quite sad; it's about losing the girl he loved to another man and how he can live without her but he'll be miserable. Not really the vibe I was going for while writing this, to be honest.