The Hunger by Whitley Strieber

Eternal youth is a wonderful thing for the few who have it, but for Miriam Blaylock, it is a curse — an existence marred by death and sorrow. Because for the everlasting Miriam, everyone she loves withers and dies. Now, haunted by signs of her adoring husband’s imminent demise, Miriam sets out in serach of a new partner, one who can quench her thirst for love and withstand the test of time. She finds it in the beautiful Sarah Roberts, a brilliant young scientist who may hold the secret to immortality. But one thing stands between the intoxicating Miriam Blaylock and the object of her desire: Dr. Tom Haver…and he’s about to realize that love and death go hand in hand.