George believes that in Panama, he was afforded a level of dignity that in New York, with Esther pressuring him to behave a certain way, he just can't recreate. Whether the draft horses are real or not, they represent George's desperate desire to look strong and in control of his world, which he believes he doesn't since Esther is the one who controls their family's finances and choices. By characterizing Esther's choice to not hand over her savings as not believing in him, he forces Esther into thinking that this is the only way to save her marriage.