A Swinging Christmas by Heather Hart
When you put a congressman together with a Detroit hood, you can wind up with an explosive combination. That's what the people at the Firm think, anyway, and they send in their best agents, Robert and Kassie, to investigate this potential threat to national security.
No strangers to alternative life styles, the intrepid pair enter the shadowy world of swingers, where they soon discover that there are secrets amongst the players that were hidden away long before any of them became involved in the lifestyle.
Excited by the prospect of switching partners, if only for an hour, submissive Kassie plunges headlong into this brave new world, only to awaken the green-eyed monster deep in her heart. And though alpha male Robert will do whatever it takes to accomplish their mission, the price of success might be to lose the only woman he has ever truly loved.