Akegata ni Shiranai Uta: Koi ga Hajimaru Doukyo Seikatsu

One day, as Haruma is making his way home from work, he saves a man, Souta, from trying to jump in front of a train. Upon discovering that Souta has no place to call home, Haruma invites Souta to stay with him for a while. While Souta is recovering from a broken heart, he finds that Haruma's kind and non-prying ways are exactly what he needed at this time in his life. Before he knows it, his heart has not only mended, but he's ready to love someone again... that someone being Haruma. Thus, the two embark on a love story that all starts by living together. (This series is written alternately by Marugari and Shiohigari.)One day, two complete strangers come together when they each make questionable decisions: Souta's of jumping in front of a moving train and Haruma's of inviting a complete stranger into his home.

(Source: Renta!)