Exciting Games (wip) immediately comes to mind. It's all about the preeminent couple exploring their newfound kinks in exhibitionism, sharing, hotwifing, and so on despite a few unavoidable issues. There's also an interesting underlying story that's starting to come into shape like how it presented itself in
Deliverance (completed), but without any supernatural elements. Also, refreshingly, the male MCs in both these mentioned titles aren't just hormone-addled teens in adult bodies letting things happen to their lifelong partners like beta-wimps. The couples in each are all
capable adults making deliberate choices for their own fun and thrills and
they decide how far things will go (regardless if anyone else are aware of that or not in their games of pleasure). In addition, it's not just the female MCs getting in on any extramarital action, the husbands can also get down and dirty almost as much as well!