I don't have a definite answer for you. It could be at any point where the story builds up enough tension or when there's a major conflict that makes him reflect and regret. Sometimes, it's a gradual realization that happens over several chapters.
Cheating on a partner is a very complex and hurtful situation. I don't have a personal story of this nature, but generally, it often starts with some form of dissatisfaction or vulnerability in the relationship. However, it's not an excuse. It can lead to a breakdown of trust that is very difficult to repair.
I recommend "The Divorce Is Ineffective: The President's Ex-Husband Won't Let Go", a modern romance novel about a wealthy family. It tells the story of the female protagonist, the wife of the president of Tianwei Group. When her good friend and her husband were entangled, she realized that she had been fooled and divorced, but she suddenly died in a car accident. Two years later, she returned to the country again and met the person who had avoided her before. In the face of the male protagonist's request to remarry, the female protagonist resolutely refused, but she was surprised to find that the male protagonist was not willing to leave her. This novel tells the story of the male protagonist's regret. It's cute and sweet. Those who like this kind of theme should not miss it. I hope you like my recommendation. Muah ~
Obviously, the ex - husband is a central character. His ex - wife is also a very important character as she is the one related to his regret. There may be friends or family members who either support or oppose his attempts at dealing with the regret.
In 'ex - husband's regret novel', a prevalent theme is the passage of time. The ex - husband looks back on the relationship with a new perspective after time has passed. Nostalgia is also a theme. He feels nostalgic for the good times in the relationship. And there can be a theme of moving on, where he has to accept the reality of the situation and move forward in his life, even with the regret.
There's also 'Before We Were Strangers'. In it, the husband - like character may have past actions that he regrets as the story unfolds. It shows how past mistakes can haunt relationships and how love can still find a way in the midst of regret. It has elements of mystery and self - discovery that make it an engaging read.
There were two novels related to the title that could be recommended: " Officer's Husband Is Addicted to Being Spoiled " and " Powerful Men's Husband Is Super Coaxed ". These two novels were both modern romance novels with novel plots and were well received by readers. However, he needed to know more about the content and evaluation of the novel to find out which one was more worthy of recommendation.