Well, the husband is the central figure. Alongside him, there could be family members who play important roles. For example, if it's the wife who is leveling him up, she is a main character. There might also be colleagues or acquaintances in the story whose actions and reactions are related to the husband's leveling up process, making them potential main characters too.
Obviously, the husband is one of the main characters as the title is centered around him. There must also be the person who is responsible for 'leveling him up', perhaps the wife or a close friend.
The husband is surely a main character. Then, there could be antagonists who might try to prevent the husband from being leveled up. And also, there may be mentors or guides in the story who help in the process of leveling up, so they could be considered main characters as well.
Chapter 80, "Outsmarting the Frost Wolf Pack", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. A useful checkpoint is the way the scene starts with How did we end up encountering a pack of Bone Spur Frost Wolves? and follows through with Xia Hong and Luo Ming turned their heads, their faces instantly....
Chapter 56, "Intermediate?", is the clearest early answer because it turns Intermediate's situation into a concrete plot event. The setup is The hardness of the Golden Frost Tree, Xia Hong had experienced it..., but the pressure keeps building through Though harder than the Red Frost Tree, under the immense strength....
Chapter 103, "The 2nd Earth-digging Realm", is the clearest early answer because Luo Ming finally turns buildup into a real advancement. It opens with In the valley mine, an iron ore the size of a palm was chiseled from... and closes on Xia Hong followed the opened path into the crowd, seeing Luo Yuan....
Chapter 143, "Picking Up a Bargain, Acting Maliciously [Three-in-One Mega Chapter]", is the clearest early answer because it turns Teng Jiao's situation into a concrete plot event. The chapter turns that into something concrete by moving from The tacit understanding cultivated over a long time allowed everyone... to Moreover, once it was trapped, it couldn't pull itself out....
Chapter 38, "Revised: Chapter 38 Please Forgive Us for Not Accompanying You", is the clearest early answer because it turns Shi Dong's situation into a concrete plot event. The chapter turns that into something concrete by moving from On the snowy night, the dense white trees pieced together the outline... to Wang Rui, Sun Xinzhu, what's going on, why are you attacking Shi....
Chapter 56, "Intermediate?", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. It opens with The hardness of the Golden Frost Tree, Xia Hong had experienced it... and closes on To think that the Wood Puppet Monster could control five or six.... The key payoff is that the chapter closes with It had already come up with a countermeasure!, which gives relationship tension a stronger narrative position and pushes the relationship tension onward.
Chapter 156, "Mirror Immortal's 10 Days, Gathering Enough Beast Blood", is the clearest early answer because it turns Yuwen Hu's situation into a concrete plot event. Early on, In the past few days, the brothers have seen it clearly.. By the end, A small bamboo leaf, no bigger than a thumb, had directly sliced off.... Inside the broader family politics storyline, the chapter closes with "Then it's purely to exclude us.
Chapter 30, "Unexpected Gains", is the clearest early answer because it turns Redwood Ridge's situation into a concrete plot event. A useful checkpoint is the way the scene starts with The logging team increased to eight people, which lifted Xia Hong's... and follows through with However, just as they turned to leave, a corpse to the west of where....
Chapter 158, "Preparation, Arrival", is the clearest early answer because it turns Lin Wan's situation into a concrete plot event. The chapter turns that into something concrete by moving from The crowd subconsciously looked around and found that Mu Dong and... to They only knew a little about the situation with the Cold Beasts.... What makes it stick is that the chapter closes with "They haven't been home since the night before last.
Chapter 136, "He Yuanhun, Yuwen Hu, Yuwen Dao (Three in One)", is the clearest early answer because it turns Arrow Bamboo Forest's situation into a concrete plot event. A useful checkpoint is the way the scene starts with From the beginning, He Meng and his group's arrogant demeanor; Until... and follows through with The Iron Arrows embedded twenty to thirty centimeters into the....