The book of scandal - Julia London

Nathan Grey, the Earl of Lindsey, has been separated from his wife Evangeline for five years when he receives a letter from a friend in Parliament informing him that Evangeline has been named in a revealing book by the Princess Caroline. She is suspected of being part of a huge scandal, and the publicity could ruin her and Nathan's reputations for ever.
Nathan decides to remove his wife from London as quickly as possible, but when he encounters her at a ball in the city he is startled by how she's changed - more mature, more self-confident, and still incredibly beautiful. He can't believe he is attracted to her. Evangeline, however, has been contemplating a romance with a kind widower, and Nathan must drag her back to Eastchurch.
An awkward rapprochement turns into a fiery battle of wills in which they settle their differences from the past, ward off a murder attempt on Evangeline's life, and uncover the treachery behind Evangeline's name being included in The Book of Scandal.