Flesh and Blood by Tricia Owens

Maxmillian Poole prefers to believe that success defines a man. It has, he believes, defined him. He has everything he could possibly want: ownership of a highly profitable and in-demand security firm, a luxurious lifestyle, and most importantly, the love of his life, fellow agent Ethan Winter.
But recently his success has been chipped at by the most unexpected source: his own father Philip Poole. After having his business and his lover nearly ruined by Philip, Maxmillian accepts that this is a problem that can no longer be ignored. Though he’d prefer to pretend that he possesses no family except for Ethan, Max knows he must take action and face the truth of his family ties. So he makes a proposal: fly to Europe and confront his problematic parents. However, once in Spain, he and Ethan are unprepared for the mother and father that they meet, nor for the mystery behind their strange behavior.