Well like the title say MangaGamer released Sandwiched by my wife and her sister.
there is still no news on their website, but they sent an E-Mail about it.
So here the E-Mail.
MangaGamer.com is pleased to announce the release of
“Sandwiched by my wife and her sister”.What do you imagine living together with your wife and your mistress (sister in law) would be like?
Depending on your choices in the game, you may end up in a catastrophe,lead a new life with your mistress, or…?We hope you enjoy a life full of sex and anxiety under one roof.
Enjoy 
[Update]
Here for the news on the Official Webiste.
