Himegoto - Secret

(from ebookjapan):

Miya was happily married and living a wealthy life in an apartment in Shirokanedai.
She was loved by her husband and had everything she wanted.
However, everything falls apart when she is reunited with Itoko, a classmate from junior high school...　

A completely new work by Masako Watanabe, a master mangaka with 68 years of experience!