The Countess Caper by Alyxandra Harvey

Polite Society isn’t ready for this Marriage of Convenience.
Lady Tessa Kilkenny’s ramshackle manor house is filled with mice and snakes and peeling wallpaper—as well as women with nowhere else to go. And Tessa will do anything to keep them safe.
Even steal a carriage from Roarke Noble, the Earl of Dartmoor.
As her first foray into being a highwaywoman, it has mixed results. She gets her cousin to the midwife just in time. But she also gets a marriage proposal.
Because Roarke needs a wife.
And with Tessa he gets more than he bargained for. She won’t tell him why she is fighting off housebreakers and stealing from earls and viscounts. Or why her disaster of a house is rigged with traps to discourage unwanted visitors.
But when those secrets put her life in danger, Roarke discovers he will do anything to save her.

A debutante turned highwaywoman, a reclusive earl, and a marriage of convenience. Can the fire between them burn hotter than their secrets?