What is the contradictory element in the story "Hills Like White Elephants?"

In this
story, a man, the American, has a conversation with his girlfriend Jig, who is pregnant. He
wants her to have an abortion. She does not, seeing the possibility inherent having a baby. The
contradiction is that he thinks it is freeing to get out of having the child, but she realizes
that they can't have everything. Every choice is in fact a choice. In the dialogue below, she
points out the contradiction in his "have-it-all" thinking. Hemingway's writing is
notably spare, and he leaves it to the reader to supply the he-said/she-said information, so I
have taken the liberty, for the sake of clarity, to supply the he said/she said below. When she
says "we could have everything," one interpretation is that she is mocking him,
because she then turns around and contradicts her (really his) words, saying that, in fact, no
they can't:

"And we could have all this," she
said. "And we could have everything and every day we make it more
impossible."

"What did you say?" [he said]

"I...