妻と息子にバレてはいけない背徳の媚熱 ～あやまちの密愛2～

Protagonist has recently retired and his family decides to go on a trip to celebrate. They arrive at their destination, a seaside inn, after a few hours of travel. They enjoy dinner and drinks together, but then his memory becomes hazy after a certain point. He wakes up feeling cold and decide to get up to wash their face. As he tries to get up, he feels a soft sensation in his hand and looks down to see his son's wife in a disheveled state, wearing a yukata. The way her yukata is disarranged and her posture appear very unnatural.