Eventually, it's revealed that the parents actually knew each other in college and that through a major misunderstanding ended up marrying the individuals who they were not truly in love with. Tangled Skein is based off the brief explanation given in the television story and tells the story of the four parents when they were in college. It should be easy to read even if you have no knowledge of the TV series. As a final note, in Japanese culture, individuals write their family name before their given name. Also, your familiarity with a person determines what you call them.
Most people call each other by their family name.
Only close friends and family call each other by their given names. In addition, certain suffixes are used to show familiarity.