Petty Revenge
The revenge plot described here reeks of pettiness, and we concur that such secrets are best kept under wraps. Granted, we only possess the information presented here, but assuming the individual didn't commit any heinous acts during the breakup, the OP takes on the role of the story's antagonist.
What happened to the fundamental right to end a relationship on one's terms? Is one to be penalized for simply not wanting to be with another? It might be prudent for the OP to safeguard this secret indefinitely, as divulging such folly could complicate future romantic endeavors.
