Well, without having read the novel in detail, it could center around the idea of self - improvement and transformation in order to be the man for a particular person. Maybe the protagonist has to overcome various obstacles like insecurities, social differences or personal flaws to achieve this goal.
Since I don't have a deep knowledge of this novel, it might also involve themes of love, friendship and self - discovery. The character who wants to be someone's man could be exploring what it truly means to be in a relationship, learning about the other person's needs and desires, and growing as an individual in the process. He may face competition or misunderstandings along the way that add to the complexity of the story.