They both know that they are going to have a child together and they believe that probably the right thing to do is to get married. They think that maybe they want to get married, but in reality, they are just trying to please the people around them. If Catherine and Henry did end up getting married it would probably be a big mistake, because the only love between them is fake. This is showing how a lot of people these days will get married, because they are having a child together or because they think that they are in love enough to get married, but if these people really sat down and thought about what they were doing, they probably wouldn't get married in the end. Many people these days do this, and end up getting divorced because they do not enjoy living with each other and they do not want to be with each other forever. This relation to what happens now-- days and what happened back in World War I times is also shown other times throughout this book.
Another time that the book refers to things happening to people right now is when Henry and Catherine pretend to like each other. Henry tells Catherine repeatedly that he loves her, but the way that he acts around her and they way that he treats him, leads people to suggest that he really doesn't. Catherine is more of something to keep Henry busy, something to keep his mind off the war, and something to comfort Henry, rather than a person that Henry really loves. As long as Henry gets what he wants out of their relationship, he figures that the relationship suits him just fine. " I'll do what you want and say what you want and then I'll be a great success, won't I?'. What would you like me to do now that you're all ready? Come to the bed again. All right. I'll come. I want what you want. There isn't any me any more. Just what you want. (Hemingway 105-106) Catherine is saying that she will do whatever Henry wants her to do, that she doesn't matter anymore, and all of her life is focused on him.