Wife Swap Wife

Gary runs into Malory, an old girlfriend, and is intrigued that she's still interested in him, even though she's married. When he comes to find out that his former girlfriend is married to a woman, he's confused, but still happy to play along. When the lesbian couple makes an intimate proposal to Gary and his wife, they find it a request impossible to turn down, even with the price they'll have to pay...
 
This is a 20,000 word novelette intended for adult audiences. Originally published in two parts.
 
Content warning: This story features graphic sex, lesbian sex, sexual humiliation, wife swapping, group sex, ménage a trois, cheating spouses, and other explicit depictions of adult sexuality. Explicit language and adult only content.
 
Excerpt:
 
"What?!" Catherine burst out. "Did you sleep with her?"
 
"I wasn't done with my story," Gary complained. His wife had been listening to him with equal parts arousal and horror.
 
"Yeah, I know. Tell me, did you sleep with her?"
 
He tried to read the expression on her face but he couldn't he was terrible at figuring out other's emotions. Holding up his hand like he was taking an oath, "I did not have sex with Malory.
 
It wasn't a bold-faced lie. It was a bending of the truth.
 
Catherine calmed down slightly. "I suppose that's good."
 
"Are you jealous?" he asked her.
 
"Jealous of what?"
 
"Jealous that my now bisexual ex-girlfriend from high school has had the opportunity to have sex with both men and women?" He spelled it out carefully for her so there would be no misunderstanding.
 
"No," Catherine replied. "And don't hold that over my head."