This is a game about a woman who ENJOYS cuckolding you. In fact, if you choose to end the cuckolding at the end of the game she consents but is clearly disappointed. Other cuck games portray it as a bad thing to some extent, but this game lets you fully indulge.
In the first game, you caught your wife cheating and let her continue due to your cuck fetish. In this game, she catches you jerking off to cuck shit and decides to cheat on you again. Spoiler Alert! She deflowers a virgin young guy who recently became her coworker. And this young 20 something year old has the intensity and stamina that you'll never have!
This leads to all sorts of incredibly erotic dialogue, like when you ask her a seriously shocking question. "Would you be dating him if we weren't married?". And do you know what she says? "Yes, I would"
Another fantastic moment is when you and your wife run into Takagi at the grocery store. Takagi thinks you're a clueless cuckold with a cheating wife, so he says nothing. But your wife says "I see you have condoms in your shopping cart! Do you have a girlfriend? Make sure you don't get her pregnant!".
This is incredibly hot because secretly Takagi is dating your wife! Its a classic kinky love triangle. You know about the affair, but Takagi smirks, thinking you're a clueless cuckold!
The game has two downsides. First, Mariko is on birth control the entire game, which diminishes the taboo. Second, the perspective often swaps between you and Mariko, making things hard to follow. If you can look past these flaws, this game is an absolute must-play experience.