Did this really happen or was it just added into the show for a better story?
shareNothing on the wikipedia pages seems to indicate that this was based in history, but I'd maybe consult some history books before making a final judgement.
Still, I'd say it's a probability that this was fiction for drama's sake.
I think that all of the Octavia's relationships on the show were fictionalized, except she did marry Mark Antony for political reasons and he did abandon her and their children for Cleopatra. Sometimes the truth is stranger than fiction.
I think Octavia's fictionalized relationships seemed very natural -- Glabius, Servilia,and Agrippa. But marrying Mark Antony only to have him leave her that way is unthinkable, but that is exactly what happened.