How the protagonist changes over the course of Malamud's A New Life

Without our even realizing it, the very nature of the protagonist (Sy Levin) and of the novel itself (A New Life) changes, evolves, over the course of the book - whether that was by design on the part of author Bernard Malamud or if it's the process of an author discovering certain truths about his own material while in the process of creation - I can't say. But think how Levin begins as a comic character, a schlemiel, a Woody Allen-precursor: in the first scene when he arrives at the college town and Pauline Gilley spills a tuna casserole on him and he has to wear Gerald Gilley's pants, too large for his frail frame (this takes on symbolic meaning later, as he engages in his affair with Pauline), or his first class, which he teaches with his fly unzipped. But gradually he becomes kind of a hot item on campus, culminating (I think) in the affair with Pauline and his deep feelings of guilt about deceiving his colleague Gerald. But the mid-point of the book he's no longer comic - though not exactly tragic, either - but more like a suffering sensitive soul, a Young Werther, a romantic hero. He's obviously very attractive to Pauline, and a more than competent sexual partner and lover - but, to Malamud's credit, he doesn't make Levin a Lothario, either - he's fragile and mortal and highly emotional. He thinks about how he can remove Pauline from her marriage, and he suffers from her absence, and then - at the point I've just reached - he learns he wasn't the first of her faculty affairs. How that changes his attitude toward her, we'll see in the next chapters I guess - but he seems both disgusted and in some ways humiliated - there was nothing, perhaps, so special about him after all - Pauline may just be a sexual adventurer, playing with fire.