@NobleWolf
Are set to marry each other for political reasons (we'll call them Person A and Person B). The way it happened was completely by accident, but it's done and in a way that there was no taking it back (at least at the time). It turns out that Person B has someone she would rather be with instead, same with Person A. Problem is, the one Person B wants to be with had been officially pronounced dead by his own country, and is living incognito. Though it happened years ago, said country might not appreciate knowing that the guy's actually alive. Also, Person A and Person B are both in positions of power, and have a lot to gain by going through with the marriage (alliances, benefits for their families, etc.)
How could Person A and Person B break the engagement and appease all parties without doing that "I love him so deal with it" cliche? (I know this is a situation we've all seen before but I want this to be done right)