Dr. Juvenal Urbino also, kind of, sort of fits into the role of antagonist. It's the classic story of two men competing over one woman, after all, and we're on the side of the lovelorn poet. He is the more sympathetic of the two suitors – he's romantic, passionate, and a little bit nerdy. Dr. Urbino is such a hotshot that we sort of hate him for it – he's rich, good-looking, and super-confident. He has everything. No fair! Our hero Florentino basically wants Dr. Urbino to hurry up and die already so that he can make a move on his girl. Right?
Whoa, whoa, whoa, you say. Back it up a little. Didn't we just make a very convincing argument that Dr. Urbino is one of the protagonists of the novel? Isn't it significant that Dr. Urbino's relationship with Florentino isn't very…well, antagonistic? You've got a point. (See, isn't this fun? In a novel as complex as this one, there's plenty of room for debate.) Remember the scene where Dr. Urbino chats with Florentino in his office for ten minutes, and Florentino feels "pangs of grief at the thought that this admirable man would have to die in order for him to be happy"? Rather than seeing the doctor as "his personal enemy," Florentino comes to understand him as one with whom he shares a common passion – they are "victims of the same fate" (4.77).
So, if Dr. Urbino isn't Florentino's enemy, who or what is? Could it be death? Time? Old age? Fate itself? What do you think?