I forgot the name of this manga. I am pretty sure there was also an anime version of it. It is similar to Tsugumomo but the main character is the son of a priest if I am not mistaken. The boy is similar to Kazuya in Tsugumomo in looks. He has a childhood friend /cousin who is atheletic and has short blonde hair. Her family seems like they run a resort or bath house and seems like her father and his father are brothers. It seems she goes to an all girls school and she is in love with him but he seems to be in love with someone else (female lead). I don't remember anything about the female lead and I don't remember if it was a fantasy manga but the time setting is about the same as Tsugumomo and Kannagi.

Also the manga and anime is more than a few years old. the main character is from a priest family like Ushio in Ushio to Tora.