TLDR Shun had NTR fetish, tells wife Miki about it and she says isn't her thing but wouldn't allow things like kiss or creampie, with the help of an old friend and college classmate Yuko they arrange a party with cameras set up to allow the husband to see and as the NTR course goes, everything goes wrong and Miki does everything she said wouldn't do. Husband despairs and regrets his decisions and that moment in the middle of the night Yuko appears and tells she left the party but Miki stayed, seduces Shun telling to choose between Miki and Yuko. Shun gives in as Yuko tells him she would never betray him like Miki did (Yuki confessed to Shun back in college but he rejected her because he has feelings for Miki, so there's a chance Yuko used Shun's NTR fetish and being Miki's best friend to get rid of her). Shun has sex with Yuko who convinces him to impregnate her and take responsibility, that she'll retrieve Miki's ring and take it for herself (MC just at the end notices Miki never had the ring on her) and accepts that his marriage with Miki is done for and his fate as he keeps cumming inside Yuko while Miki has a 3P and became their pig cumdump.
Thanks for the upload! So the only work from the artist that hasn't been posted here is this one: 夫とは離婚してるんだもの…~さかりのついた元配偶者~ https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_245665/