And today is the last day he will see Ella.
He better not screw up on the last round of the challenge or else if he will lose today it will take another whole month of continues dating with Ella twenty times, and that's cumbersome given Ella's personality. That would establish higher chances of Catherine finding of the truth of the rendezvous. Even though he was not directly cheating with Ella on the physical and sexual level, still in Catherine's mind and the way she thinks it will be pure cheating.