To Sir, Without Love: I'm Divorcing You, Vol. 2 (manga)

When Arnald receives a letter of divorce from the wife he has never met, he decides to strike a wager with her instead. After all, he’s heard rumors of this temptress and he’s not one to take a loss. It’d be a shame to let Byletta go without seeing what she’s like for himself. But the more time Arnald spends with Byletta, the less he understands her. Just what is this feeling growing inside him?