@TopNepp
Basically, marriages in the past were considered invalid if you didn't "consummate" it, aka have sex. Saying you never had sex basically means it wasn't a real marriage, so Shuli tried to use that to have her marriage cancelled to shift authority as head of the house to Jeremy, where he could have requested a "duel of honor" with his hand at stake (meaning that one of the knights- presumably Albert- would have fought for him, and if Albert won the fight, he gets to keep his hand.)
Since the empress basically only pressed this far to test Shuli and never had any intention of cutting off Jeremy's hand in the first place she called the trial off when things started getting too heated.
TL;DR Marriages weren't considered legitimate unless you fucked and Shuli tried to use that to make Jeremy head of the house to save his hand, Empress decided to call the whole thing off