Why didn't Rick remain married to his young bride?

Rick and his wife married when he was in his early twenties. For a few years the marriage worked. Then Rick got a job seventy-three miles from home and he was gone for long hours. He came home one night to the news that she thought she was pregnant. Rick panicked. He realized that he was too afraid to ever be a father because he never wanted to be like his own. And so, the couple split.