I haven't read this novel specifically. But generally, a 'villainous husband' in a novel might be a character with complex traits. He could start off seeming bad but then have a character arc where he shows redeeming qualities or there could be a deep love story behind his so - called villainous behavior.
Since I haven't read it, I'm not sure. But it might have a villainous husband as one of the main characters, and probably a female lead who is somehow connected to him, maybe his wife.
The story of 'Marry My Husband' manhwa focuses on themes of love, betrayal, and self-discovery. The main character has to navigate through various obstacles to find her true happiness.