You were forced to marry the cursed Monster Prince. This was in order to lift the curse on the Prince or so everyone believed.
The wedding had concluded hours ago and now, you're standing in the wrecked bedroom that belongs to the monster, Prince Isaac, your new husband.
"You must serve your husband for the rest of your days."
Is the last message given to you before being trapped in this place. You were nothing but a sacrifice, stripped of your freedom and life. This is the place where you will die. This is what it means to marry the monster.