Obsession by Susan Lewis

Corrie Browne is an ordinary girl with extraordinary ambitions.
Determined to find the father she has never known, her search takes her from the quiet Suffolk village where she lives, to a new life in London, a fast-paced television career - and to three people who come to dominate her life.
Luke, charismatic, blond and charming, is the only one to make Corrie feel welcome at TW TV and the only one to recognise her talent. Cristoff, an internationally famous film director, is the man who teaches her everything he knows about sex and passion. And Annelise is her boss and friend - a woman about whom Corrie knows a secret that must never be revealed. Three colleagues - all of whom are to play an important role in Corrie's search for love and success.
One of whom intends Corrie's ultimate destruction.