I Taught You Carefully, so Why Are You Obsessed?

Let's Reform the Hopeless Male Lead Before the Heroine Returns! I, who was the 'villainess' in the original story. After being infuriated by the frustrating ending, I was hit by a reincarnation truck and possessed the ex-wife of the regretful male lead, 'Ian Cloud.' But this guy is even more stubborn and terrifying than I expected. 'What is it?' 'Not needed.' 'Forget about it.' ... Aren't we just going to repeat the frustrating mess of the original? So I made a resolution. I will reform this hopeless regretful man before the heroine returns! But... 'Did you plan to leave me all along?' '...What?' 'Did my wife not tell you? In a true relationship, each person becomes the one and only for the other.' He gently kissed the palm of my hand. His languid indigo eyes were fixed on me. 'I am solely yours.' '.....' 'So, you must also become solely mine.' Seeing his glittering gaze, I thought. This seems to be very wrong. No, more importantly, I never taught him to be obsessive!"