First off, you should have thought of a way to reverse this before doing it, since it seems your intention wasn't permanent.
Jinxes don't have to last forever, if you feel that the jinx has done what you wanted, then simply believe that it is done inflicting a curse upon your ex.
If you want to take the hex apart, cleanse the box, and sweep out the dust you left behind. Possibly have the ex do a cleansing bath of some sort. Though, those probably aren't necessary.