My basic idea (which of course is up for discussion) is my male character is married. His wife being one of the female characters have been married for maybe 10 years or so. They don't have any children reasons for that can be discussed if needed. While still loving each other their love life has fallen into a rut and both are growing bored unknown to each other. He starts to look for excitement in other women and unknown to him so does she. The second female character would be the new love interest of both. At first she just knows that they are married but not that it is to each other. As the story progresses they would find out the truth and eventually come to terms with it and turn it into a nice threeway relationship.
We could also add a supernatural or fantasy aspect to this. The wife could be a witch or fae or anything of the player's choosing. My character could be a were of some type, or a sorcerer, or something, certainly open to what the players desire. The other female might be a succubus or such or player's choice.
I'm open to input and discussion of all aspects of this story.