The fifth novel in the Knights of Champagne mini-series is coming out in October 2016. It tells the story of Francesca, who was first introduced in the second of the novels. Francesca is married to Tristan le Beau, count of the isles, and their marriage is in deep trouble.
Here is the cover blurb:
Wearing his ring again…
When a shocking revelation reveals Francesca's illegitimacy, she worries for her marriage to Tristan, Comte des Iles. Her heart in tatters, she awaits her husband's return… Will he request an annulment or give their union a second chance?
Duty has kept Tristan from his beautiful wife's side for far too long, but the memory of her touch is seared into his soul. Now, with malevolent forces working against them, it's more important than ever for Tristan to show Francesca that he'll never let her go!
This link takes yo to a piece on Bookish Jottings about the series.