The Tree of Reluctant Partings

(from ebookjapan):
Benie, who is leading a comfortable life as the wife of the president of a company, is often troubled by an unbearable sense of loneliness. One day, when Tetsuro Ike came to visit her on company business, a casual gesture made Benie feel the intense provocation of a young man...! An unforgivable love that runs through the beauty of disorderly tones.