Mother's anus dedicated to her beloved son

It's been ten years since my husband died. Hotaru, a mother, finally started thinking about happiness as a woman after her only son, Tsuneharu, got a job. However, she still has feelings for her late husband towards her boyfriend, Seiichi, and even though they have a physical relationship, she is unable to take a step forward. Just when I thought that things couldn't go on like this, Tsuneharu and Seiichi suddenly got into a fist fight. Hotaru is surprised by this sudden response and asks why, but then she learns of Toneharu's secret feelings for her...