https://www.dlsite.com/maniax/work/=/product_id/RJ01613617.html
https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_758597/
https://www.melonbooks.co.jp/detail/detail.php?product_id=3607685

Base +28, jnbarnes +3

(同人CG集) [地下室 (GADEN)] 搾精義母に生種付け 妻公認の代理懐胎

Base +12, stupid army +11, Starr12138 +7

Male: Cheating

Maya asked her mom Myuki to be her surrogate after finding out she is sterile, Maya wasn't comfortable with a stranger being the mother of child so she asked her mom and Myuki accepted, Maya's husband Kazuya was reluctant to inseminate Myuki at first, not being quite on agreement over impregnating someone else other than Maya but Myuki invited Kazuya for a casual outing to make his worries lower a little, it worked too well since despite making sure to avoid actual intercourse at first, just keeping it a semen extraction to send to a lab, Kazuya let his desires for his mother-in-law get the best of him, wanting to have sex with her, Myuki falls too since it has been a long time since she had any.

In short, Maya consented to her mom being impregnated through insemination, she doesn't know this became a secret affair between Kazuya and Myuki, I'm making this clear since the work's title might make some people think everything here was done with Maya's approval.

No cheating tag for mom, Myuki is a widow, she wears her ring out of loving remembrance, but does remove at the very end when she fully falls for Kazuya, wanting to have a second child to be hers, not a surrogate for Maya.

Base +21, mombastical +7

thank you~

Base +6