So when you go into the Lustful Desires folder to play the game, there will be a folder at the top titled game, open it, then the second folder down will be called saves, if you open it all it will have is your saves. So when you have the new update, repeat the steps then click and drag the saves folder from the old files into the new one.
Just to highlight it: This trick works until the current update (and presumably again afterward), which was uploaded onto itch.io after your comment, but it will not for the next one. A bit of a bummer, but other than some recipe grinding I don't mind; after all, it's part of the nature of a game in development.