Everything in the story indicates that the man definitely wants the girl to have an abortion. Even when the man maintains that he wants the girl to have an abortion only if she wants to have one, we question his sincerity and his honesty. When he says, "If you don't want to you don't have to. I wouldn't have you do it if you didn't want to," he is not convincing. From his earlier statements, it is obvious that he does not want the responsibility that a child would entail; seemingly, he strongly wants her to have this abortion and definitely seems to be very unresponsive to the girl's feelings.
On the other hand, we feel that the girl is not at all sure that she wants an abortion. She's ambivalent about the choice. We sense that she is tired of traveling, of letting the man make all the decisions, of allowing the man to talk incessantly until he convinces her that his way is the right way. He has become her guide and her guardian. He translates for her, even now: Abortion involves only a doctor allowing "a little air in." Afterward, they will be off on new travels. However, for the girl, this life of being ever in flux, living in hotels, traveling, and never settling down has become wearying. Their life of transience, of instability, is described by the girl as living on the surface: "[We] look at things and try new drinks."
When the man promises to be with the girl during the "simple" operation, we again realize his insincerity because what is "simple" to him may very well be emotionally and physically damaging to her.