Cuckold game: "I'll definitely take your wife..."

Her husband, Keiichi, was tasked with investing heavily in a foreign fund. Oki, a colleague, was a close friend and rival. However, one day, Keiichi is forced to lose a huge loss. Oki suggests Keiichi to play a certain game. He seduces Keiichi's wife Mayu, and if he rides, Oki wins, and if he doesn't ride it, he will give up the deal... Keiichi was absolutely confident. Mayu said she loves herself. Then, when the game begins, Oki skillfully disrupts Mayu's heart and plunders him...