"Flawless Design" by Alina Popescu

Shamsiel is an angel bound to Earth as punishment for killing another angel and human out of jealousy.  He meets Blake, whom he assumes his human, but does not want to get too close for fear that he will take another life.  I don't want to give away more than that, but I enjoyed the way the author conveyed the characters and their fears of not being good enough for each other.  Short but well written.  35 pages (Kindle edition).