You’re not bothering, you’ve submitted the request at the right time ;)
Sad & Angst are definitely entwined in this fandom, so as much as I would have loved to post ‘all sad’ ones I couldn’t help to notice we have 8 lists of ‘angst' and 4 lists of ‘heartbreaking' with lots of fics with the same theme you've requested and that will surely break your heart… if that's your thing XD
The light in your eyes by Tambear
Merlin is a teacher and Arthur his student (I don’t want the age gap to be really big though like this is Merlins first year teaching or something) and Merlin thinks that Arthur is a total slacker and puts no effort into his work. Except he does, but Uther is abusing him at home and it makes life a lot more stressful and leaves less time for work.
Untitled by Anon
Arthur is a cop: one day he assists to a murder of a child (the same age of his son) and when he comes home to his family he collapses in Merlin’s arms crying. The mere thought of losing his son, or Merlin, gets more real when he experiences death right in front of his eyes. Merlin knows how to handle Arthur and soon he shall be ready for another day, another battle.
After The Storm by cait_roswen
Merlin and Arthur spend one night together, but Arthur skips out on his duties and Camelot becomes overrun by Morgause’s soldiers. They lose the Keep, and are forced to flee. This is the story of how they survive the winter, and try to find each other again in the wreckage of their destiny.
Seven by Anon
Merlin and Arthur lose their only son Leon.
Pianos are Made for Falling by fishwrites
Arthur is a world class violinist, trapped in Sydney, Australia, by his fear of flying. In the wake of a mediocre concert, vicious critics and with barely a month to go before his next (hopefully reputation-saving) recital, Arthur is almost at breaking point. When his accompanist, Morgana, breaks her wrist in a car accident, Arthur is more or less doomed. And the story begins, when the Maestro at the conservatoire, Gaius Stresemann, recommends his protege Merlin Emrys to step in. Merlin, who plays by ear, as he pleases and really just wants to be a kindergarten teacher.
Camelot needs a bridge by ansera
Arthur Pendragon’s life is changed when he befriends the new geek in school.