When It's True by Barbara L. Murphy

Happily married couple Beth and Kelly get a last-minute visitor for the holidays in the form of Beth’s womanizing ex-girlfriend Jackie, who boldly announces that she plans to walk away from this visit with more than just good memories. When Kelly’s sister Paige arrives a day later, the sparks fly with Jackie. Kelly is determined to convince her sister that Jackie is not to be trusted. But Paige sees a different side of Jackie and puts her past heartache aside to give Jackie a chance. Meanwhile, Beth and Kelly rely on the strength of their love to support each other through an unimaginable ordeal.