U for Unrequited Love
First of all, what does it even mean? Basically it means your love for someone is not reciprocated: You love someone but they don’t love you back. In some cases they might not even know about your feelings because you know you have no chance or because the love is forbidden and you hide your emotions from them. The internet sums it up well:
As usual, everything bad also has a good side. While it is undeniable that unrequited love leaves broken hearts behind and means emotional stress for everyone involved (the person in love as well as the object of their desires), this very feeling often unleashes a bout of creativity or even makes the person realize they’re worth much more and should search elsewhere. These articles confirm that some fabulous art has come from unreciprocated love: http://www.washingtonpost.com/opinions/how-unrequited-love-can-make-us-more-creative/2015/02/12/525b38c2-ab2a-11e4-9c91-e9d2f9fde644_story.html
http://www.litdrift.com/2009/10/29/it-hurts-so-good-%E2%80%93-why-requited-love-is-less-interesting-and-15-favorite-instances-of-unrequited-love-in-fiction/
And here are some great books that deal with unrequited love: http://www.theweeklings.com/lisa-a-phillips/2015/02/11/the-50-greatest-unrequited-love-stories-ever/
Last but not least, a song with a perfect title and matching lyrics: I Can’t Make You Love Me (If You Don’t).