The Rakehell of Roth by Amalie Howard

As owner of the most scandalous club in London, the last thing the notorious Marquess of Roth wants is a wife. Keeping up his false reputation as a rake brings in the clients with the deepest pockets—money he needs to fund a noble cause. Even though everything inside tells him not to leave his beautiful, innocent wife behind at his country estate…he must.
But three years later, tired of her scoundrel of a husband headlining the gossip rags, Lady Isobel Vance decides enough is enough. She is no longer a fragile kitten, but as the anonymous author of a women’s sexual advice column, she’s now a roaring tigress…and she can use her claws.

Isobel decides to go to him in London, channeling her powers of seduction to make him beg to take her back. But she didn’t expect her marauding marquess to be equally hard to resist. Now the game is on to see who will give in to the other first, with both sides determined like hell to win.