To Catch a Rake by Lavinia Glen

Lord Andrew Radcliffe swore never to be trapped into marriage—especially not by a scheming debutante. But when a luscious beauty invades his private refuge in a blatant attempt to compromise him into proposing, her undeniable allure makes him stare a bit longer than is wise. If she weren’t a lady, he might feel tempted to make a very different kind of offer. And yet, as they teeter on scandal’s edge, she urges him to escape before her mother catches them together.
Her unexpected but utterly refreshing warning changes everything he thought he knew about women. Intrigued by her honesty, Andrew is drawn to the one woman who clearly has no intention of ensnaring him.

Or does she? As Andrew quickly discovers, he may just be the willing prey to her irresistible charms.