Typical American is in many ways, not about an American per say, but rather, a portrait of how America works as a mentality. The question is about the American Dream, and the reader has been recruited by the author to help analyze the value of life in need, life in adequate success, life in outrageous success, and then to analyze the pattern as it develops, because after the novel is over, the reader has to pick a fate for themselves of the three. For Ralph, the decision is more narrow. The decision is "Do you want a family, or do you want unimaginable wealth?" and Ralph should choose carefully.
Is the choice so simple as that? For Helen, it seems to be. There are ethical boundaries that he crosses in his days that prevent her from respecting him. Another way of saying that is that her "villain" senses are tingling. She believes he has become evil, and he doesn't see it that way, so they fight, and in the end, we see why he doesn't perceive his transformation—the way he damages his community is brutal and absolute, but technically, he could dodge the blame still.
For instance, his wife falls out of a window. Now, is that perfectly his fault? Well, there was some accidental quality to the whole scuffle, but beside that, one might suppose, it isn't his fault, because he was emotionally overwhelmed and had a perfectly understandable moment of pure violent panic. Then again, one might say, "What if he had managed his temper with therapy?" and then it becomes clear—he did a have a choice. He had a long list of choices and continually cornered himself into emotionally desperate space. The women probably think he is arrogant, but secretly, he knows he is dying inside trying to find some meaning to his difficult life, trying to taste a bit of success somehow. But, the consequences of his action are that he hits Theresa in his car, and his wife is almost dead from his violence.
