The Man Who Made Husbands Jealous: Rutshire Chronicles, Book 4

Lysander Hawkley combined breathtaking good looks with the kindest of hearts. He couldn't pass a neglected wife without rushing to the rescue which invariably led to ecstatic bonking, which didn't please their erring husbands one bit. Let loose among the neglected wives of the ritzy county of Rutshire, Lysander causes absolute havoc. But it is only when he meets Rannaldini, Rutshire's King Rat and a temperamental, fiendishly promiscuous international conductor, that the trouble really starts...