Jake no doubt would have preferred to have it differently, but he is accepting of the way it stands.
The hardship and the poverty that is so widely spread in that area during the post war time causes the people to lower their moral standards.
This story takes place immediately after World War I, a time of great hardship.
This hardship results in a digression of values both morally and socially.
These two steers symbolize Robert Cohn and Jake Barnes. This steer is beat up by second bull, representing Mike's bullying conversation with Cohn after the bullfight.
Also, after the steer gets up, it just stands there, removed from the group (including the other steer) as if not accepted. This steer is the one responsible for grouping all of the bulls together.
But her actions seem always to end up hurting her, and she runs back to Jake.
Jake knows that he will never be able to have her for his own, and he accepts this as fact.
This resembles the fact that Jake is the first to introduce Bill into the group.
In the novel The Sun Also Rises, Ernest Hemingway describes a couple who share a very strange and distant kind of love for each other.