In the book the Great Gatsby Tom and Daisy are married however they have an interesting relationship. Daisy and Tom don't actually share feelings for each other because Daisy married Tom for money. Tom doesn't share feelings for Daisy because he has a mistress in New York while they are married. Tom goes and visits here about once a week because he has nothing better to do on Sundays. When they see each other they go to there own place and not to Tom's house.
Mr. and Mrs. Wilson are another example of unrequited love because Mrs. Wilson doesn't love Mr. Wilson at all. In fact Mrs. Wilson is Tom's mistress and has real feelings for Tom. When Tom comes to get Mrs. Wilson from the garage they live in they get really close when Mr. Wilson goes and does something but when hes there they are seperated a little bit so he doesn't suspect anything going on. They whisper to each other the place where they're going to meet and then once they meet up they head to the train and then the place they're going to stay at. Mr. Wilson has no clue that they're having an affair and Tom thinks he's to stupid to find out.
This subject can be talked about in a lot of peoples lives because certain circumstances make you have to be with someone you don't want to be with. Some people are just greedy and marry someone for they're money so they're set for life and don't have to work. People like this don't share feelings for the person they're with.
Sources- "The Great Gatsby" by F. Scott Fitzgerald