Dexter is a man of action, a self-made man who can change his life by going to an elite college and investing cleverly in business. But he can only do those things because he is, specifically, a man. Judy Jones has the same kind of restless, melancholy spirit that Dexter does. But because she is a pretty lady, she becomes an object to be admired (by men like Dexter). Her great talent is her physical beauty, and it is through her body that she tries to find emotional fulfillment. What is this, the 1920s? Oh. Yeah, it is.
The other main female character in "Winter Dreams," Irene Scheerer, represents another possible, socially acceptable role for upper class women in the 1920s: wife and mother. Irene is welcoming, friendly, and clearly destined to be great with her kids. While in many ways, Judy and Irene seem like absolute opposites, they share the same essential trait. Their characters are defined in relation to the story's central male figure, Dexter. We have no sense of how Judy and Irene think as rounded characters. The fact that they are women limits their ability to move through multiple social spaces the way that Dexter can.
Judy is a total diva. But her assumption that beauty means (or should mean) happiness is just the 1920s female equivalent to Dexter's belief that money means happiness.
Judy is looking for the same kind of emotional fulfillment from her many partners that Dexter seeks in his business investments. Their two separate responses to the same feeling of loneliness and isolation is the result of gender difference.