Rika met her husband, who was her senior in college, and they began dating after falling in love at first sight, eventually getting married. During their cohabitation before marriage, they enjoyed a frequent and active sex life, a rhythm they maintained for some time after marrying. However, about half a year ago, their intimacy began to decline, and now they only have sex on weekends. Rika assumed her husband was simply exhausted from work, but a recent incident made her notice something was off. In the past, they always spent their days off together, but lately he's been going out alone more often, saying he's off fishing with coworkers. Then one day, she unexpectedly spotted him at the nearest station—and what she saw left her shocked.