https://www.dlsite.com/books/work/=/product_id/BJ01021341.html
As always, please support the artist and buy his works.

Netorare Wife - Unable to resist her husband's son, she keeps getting fucked all night long!

"Try moaning like you love me like you did just now."
Misa is waiting for her husband to come home, looking forward to their big anniversary. However, her husband is busy at work and doesn't come home. She is so lonely that she drinks herself to death at home and falls asleep on the sofa....
Then she woke up and said, "Oh...is my pussy ticklish? Misa wakes up and thinks that her husband has touched her. Misa is in agony because she is loved more intensely than usual, but it turns out to be her husband's son Ryosuke! Misa tries to resist, but she can't help but feel a tingle when she feels a rod penetrating her for the first time in a long time!
She tries to resist, but she can't help but tingle at the sight of Ryosuke's cock, which she hasn't been able to tell her husband about.... Ryosuke's training escalates even further!

This author is severely underrated. His work is excellent, both in art and plot. Someone should comission a translation for one of his works.
If anyone can recommend a good and safe place to comission a translation, perhaps I myself will in the future.

"her husband's stepson"

so the son is from the husband' ex-wife

Base +8

No, it was my mistake. Its actually her stepson, the husband's son.
Japanese has a tendency to translate "stepson" as "son-in-law, "stepbrother" as "brother-in-law" and so on and so forth.
This is why I didn't notice the error and just corrected "her husband's son-in-law" to "her husband's stepson", replacing one error with another.

Its fixed now in the OP, sorry for the confusion.

Base +7, yupokamusi -8, Xafnir +6