A Poster He or I wrote:The main theme of the book to my mind is about the possibility of establishing meaning and purpose by embracing life's Dionysian aspects from an Apollonian platform, if that makes any sense.
Although it's been a while since I read it, I recollect identifying with the feeling of despair as well when the narrator describes this relationship. If I remember correctly he's the product of a childhood resembling the one of the narrator in "Demian". In the sense that he is by many means the product of a middle/upper-class upbringing, consisting of a kind of light, neat and very orderly environment (which is why he rents a room in a house reminiscent of his childhood). In my opinion his type of upbringing is one of the sort where you are expected to achieve a certain amount of success in society. In addition to this he has a sort of antagonistic personality, a force that makes him want to experience the more, as you say, "Dionysian" parts of life, he's in need of the tension and excitement that follows from those more "adventurous" experiences in life, which kind of collides with that orderly upbringing. And I think it's important to emphasize that there's a huge conflict between these two forces. I think that's why I related so much to this book, and I think many people can identify to a certain degree with this conflict of identities. We tend to see our personality as one unit, but in my opinion our personality consists of different personalities and therefore your choices always has some other personality pressing their opinion or judgment on your choice. And I believe that's one of the main themes of the book, that every time he acts on his, as you articulated it "Dionysian" forces, this other person this "natural product" of his upbringing, that wants to be a regular citizen and wants to fit in and conform with the values and conducts of the everyday man, judges him and looks down on him with a kind of resentment. And oppositely, if he tries to follow the life of the other personality or identity, the wolf or the "steppenwolf", always stands outside scratching his door, and mocking him with his howls. So no matter how he conducts his life he feels a form of shame/guilt.
And as for him being 40 instead of a teenager or a young man on the edge to manhood I think is that he's the symbol of the middle-age crisis. Of all these "rebels" that doesn't want to conform with the dull average life of the common citizen, but eventually has to and maybe does so a bit involuntarily because he is, as I said, expected by the nature of his upbringing to achieve some kind of success and by that are pressed into this society. This again results in those repressed thoughts and needs coming back to haunt him later in life, like it does for many men in that age. But I'm only 21 years old, so I can't say this by my own experiential judgment, but I'd imagine that's one of the points Herman Hesse wants to make. It's a feeling that stuck with me as I read it at least, maybe especially due to the point I am in life, kind of on this edge.
This whole matter of combining and harmonizing those two forces within you is the way I see it an immensely intricate thing, and a source of crisis and despair within many peoples life's.