You can find the link to it here:
Demon Chronicles: Serephin
Serephin wanted to be loved. Being half human and half demon made her an outcast. So, together with her two best friends, she heads to the human world hoping that since they look human, they will find a home there. But nothing is as they read. They are no longer outcasts, but if their demon blood is discovered they will become the hunted.
Morgin and Drallan vow to protect Serephin as long as she agrees to become their mate. Serephin can’t admit what she is and her mates have secrets of their own. Can the threesome find a way to trust and form a bond that includes love?
This one is book one in a trilogy. It is menage. Though the heroes are brothers, they share her and do NOT indulge in sex with each other. I hope you'll give it a chance!