The Great Conspiracy

This conspiracy is rather odd, in that a second person other than our protagonist may fall victim to it. The world has decided to play matchmaker with our protagonist, and for some reason they want to pair her up with a member of her own family. It could be her father, or her sister, or even her son: gender and age is less important than the fact that she will be having sex with a close blood relative, and often at that. The relative may or may not be in on the conspiracy themselves, but either way the end goal is to somehow get the two in bed together, and hopefully start an incestuous relationship.

Of course, part of the conspiracy is the secretive nature of it, and they will not want the protagonist to know that she is being manipulated into having sexual relations with her family. So they will insist that is still taboo, at least officially, even as her husband gets scheduled for a three month business trip overseas, her best friend slips aphrodisiacs into her tea, and her favorite talk show 'offhandedly' brings up a story about how the risks of incestuous sex are over-exaggerated.