True Betrayals by Nora Roberts

Dear Kelsey: I realise you might be surprised to hear from me . . .
Kelsey Byden, divorced at just twenty-six, isn't looking for any more drama. But then she receives a letter from her mother, Naomi. Not so unusual - except Kelsey has always been told that Naomi was dead . . .
During an extended visit to her mother's beautiful horse farm in Virginia, Kelsey begins to untangle a lifetime of deception. Who can she trust, when those she loves have lied to her for so long?
To complicate things further, Kelsey is falling dangerously in love with Gabe Slater, Naomi's handsome and intriguing neighbour. But love and lies are a lethal combination. If Kelsey has any hope of a future with Gabe, she must first understand the terrible truth about her past .....