he was glad that he hadn't done anything to destroy the evening's sweetness

Can you tell me where this is in the book?

As they talk about Ned and Ruth for long time,Ethane imagined of Mattie,Mattie was sewing the piece of cloth, Ethane touches it and they have a some kind of psychic communication through the cloth, so Ethane ,in a daze kisses the end of piece of cloth with his eyes closed but when he opens his eyes Mattie was rolling up the piece of cloth and preparing to leave the room and she goes upstairs,telling him goodnight.This explains that he hadn't done anything such that destroy the evenings sweetness.