Why is gerry the antagonist of the story cold equations?

I don't think Gerry is the antagonist of the story but I can see how someone might think that he is. The whole reason why Marilyn went on the EDS ship was to visit Gerry, and it was very hard for her to watch Gerry find out about the situation. I think the antagonist is the cold equation itself. It's interfering with the protagonist (EDS pilot) because he doesn't want Marilyn to die.