The Last Lord Standing by Diana Lloyd

Always the rogue and never the gentleman, Kerrigan Northam doesn’t worry about anything beyond his own pleasures. But lately, his noble friends have been considering marriage—specifically, the charms (and generous fortune) of the refreshingly pert Lady Olivia Liberty Chalford. Now they want Kerr to keep her from considering any other eligible suitors…by courting her himself!
Libby is averse to the very idea of marriage. Why be auctioned off when she has a far more enticing—if scandalously modern—plan for her future? So when she’s rescued by a wickedly dashing gentleman who claims to be something of a scoundrel, Libby thinks she’s found the perfect partner in crime…
It’s the perfect ruse. Libby gets a secret accomplice and Kerr’s in the uniquely coveted position of being able to kiss the comely, spirited Libby as thoroughly—and as often—as possible. But as their courting charade continues, Kerr’s gone from wondering how long until she discovers his secret…to how long until he’s madly in love with her.