This dev makes other games. They're not free but some of them do involve compersive queaning and harem elements. And they're all good games too.
In particular I like the plot of Ouroboros: In a setting where our protagonists are trapped in a place where time cycles repeatedly and resets their memories, in different instances of the time loop our protagonist usually ends up with one of a few women each time, but not consistently the same one. When they eventually defeat the magic that resets their memories, each of them has centuries' worth of memories with the male lead... so rather than fight about who is his true soulmate and eternal best wife, they agree all of them have a valid claim and their shared experiences in the time loop have forged a bond between the group outsiders couldn't understand anyway. Harem ensues.
I'm hoping one day the dev's series Crimson Gray is continued, because while it is decidedly not a cuckquean series at the moment, the dev mentioned that at some point the game would attempt to explore how the yandere archetype could work in a partner-sharing situation (other than murdering everyone, that is).