A married woman personal trainer seduces me with her beautiful butt and a devilish smile, reverse NTR

Recently, my wife has been on a diet after watching a video site. The female trainer shown in the uploaded video is called Mizuki and apparently has a personal gym open. My wife and I ended up going to the gym as a test. It seems that Mizuki runs the gym on his own and he kindly guided me in training. However, my open chest and the strange close distance made me desperately try to maintain my rationality. To me, Mizuki-sensei has made a fascinating suggestion that there will also be one-on-one lessons...