Furin Yuusha ~Sono Furin ga, Sekai o Sukuu~ The Motion Anime

The protagonist, who had longed to be reincarnated in another world, dies one day while saving someone.

The protagonist reaches heaven and is happy to be reincarnated in the other world of his dreams, but the mission given to him is to become an "adulterous hero" who saves the world through "adultery".

The protagonist reincarnates while thinking that adultery is no good no matter what but in his new world, he meets married women who are not sure what to do with their bodies...