Runaways — Lex Valentine

Werewolf Ranulf Verlaine and his longtime lover, vampire Griffin Rothschild, have sworn they will fight to stay together if either discovers another is their mate. When Ran meets beautiful vampire Dante Ducoin on a train from Prague to Paris, mating lust explodes between them and Ran forgets the pact. He forgets everything but sinking into and surrounding Dante, who is equally lost in Ran. Newly bonded, the pair run away to New York City.Griffin chases after his lover, pulled by a metaphysical force. When he finds Ran and Dante, mating lust shifts their bond to a triumvirate. The three can't keep their hands, or anything else, off one another. But lust isn't everything. For the triumvirate to thrive, Dante must carve out a place between two men who have been lovers for years, Griffin must share the only man he's ever loved with a woman, and Ranulf must balance his pack responsibilities with his love for his mates.