Preferably, corruption of someone's girlfriend of wife, but cheating isn't necessary. Focus is corruption, not cuck/infidelity.
No 3D, pre-rendered CGI, only 2D art.
These fit the bill the most:
Turning the Page
Armored Suit Solgante (戦甲機ソルガンテ)
In the House of Despicable Family (ケダモノ（家族）たちの住む家で～大嫌いな最低家族と彼女との寝取られ同居生活～)
Avoid anything extreme like scat, guro and stuff like that. Futa, gay, furry - nope.
No 3D, pre-rendered CGI, only 2D art.
These fit the bill the most:
Turning the Page
Armored Suit Solgante (戦甲機ソルガンテ)
In the House of Despicable Family (ケダモノ（家族）たちの住む家で～大嫌いな最低家族と彼女との寝取られ同居生活～)
Avoid anything extreme like scat, guro and stuff like that. Futa, gay, furry - nope.