Powerful Greek, Unworldly Wife (Harlequin comics)

Millie falls passionately in love with Greek banker Leandro, but soon after they get married she catches him having an affair with her own sister, Becca. It's been one year since Millie left him that day, and she resolves to return to Leandro to take the orphan of her now-dead sister from him. Even so, Millie still loves Leandro. Nothing could change her feelings toward him. But when she arrives, she sees a half-naked woman in the arms of her half-naked husband...