I'm sleeping in the river, and I see my wife Yukine being raped by her trusted subordinate, and she gets depressed and erection NTR

It's been three years since I married my beloved wife, Yukine. He was stressed out in his position as a middle manager and was unable to embrace Yukine. Yukine encourages me, but I know she's indulging in masturbation every night. One day, he invited his subordinate Saji to his house. The last train was gone, and as I was drunk, the three of us suggested that we should go to sleep in a river shape. Something might happen...I fell asleep in anxiety and excitement, but gradually I woke up to the sound of something slurping...