MUSHROOM GIRLS IN LOVE (Kinoko Ningen no Kekkon), by Kei Murayama. First published in 2013 and first published in North America in 2018.
PLOT:
In a world full of mushroom people, members generally stay within their own tribes. Herders marry herders; scribes marry scribes. Thus, when the herder Arralia marries the scribe Erriela, the marriage is the talk of both groups. Their wedded bliss is short-lived, thanks to royal machinations and the prejudice of both groups. When Erriela is kidnapped, Arralia lays her life on the line to rescue her wife and find a place where they can both live happy and free.