The love-letters to his love-interest in the past were carelessly left out in the open for said love interest, his girlfriend to chance upon and as a result, the past life connected up to that point is explained.

Main series/doujinshi:> Haibane Renmei( http://mangapark.com/search?q=haibane-renmei )

Eighteen pages of prettiness by the ever-yummy Yoshitoshi ABe.An original doujinshi.

You must never see the duke’s face. After her second husband's death, Lily is forced into a third marriage by her father. Her new husband is rumored to be a monstrous warmonger, but to Lily's surprise, the Duke turns out to be a kind man and husband. There's just one catch... she must never see his face

Because he failed to confess to his best friend, the male protagonist got traumatic sequelae of first love failure'. In order to be able to successfully fall in love in the future, he can only regain the object of the confession to relieve the happiness, but the best friend who has never thought of missing for eight years is actually a god suffering from depression.