Mary Ingalls and John Jr have a relationship on the television show. They were discussing marriage and were briefly engaged. However Mary worried that she would hold him back from his dreams of becoming a published author, and they decided to have a long-distance relationship when John Junior went to Chicago for a job as a reporter.
Mary and John Jr continue the relationship, but when Mary planned to visit him in Chicago, she discovered that he had been cheating on her and did not love her anymore. They ended the relationship and Mary returned home while John Jr. remained in Chicago working.
Mary and John did not get back together on the show. And later on in the show, he was murdered because he was researching a business corruption case and was about to report on what he discovered, and the business owners did not want the truth about the corruption to become public.