Okay, here is a link to read up on them.I must mention the fourth volume of the series The Wagers of Sin (Fortune favors the viscount) by Caroline Linden.
The Wagers of Sin Series by Caroline Linden
My Once and Future Duke (The Wagers of Sin, #1), An Earl Like You (The Wagers of Sin, #2), When the Marquess Was Mine (The Wagers of Sin, #3) und Fortun...
www.goodreads.com