Web of Desire by Sophie Danson
Marcie thinks she is happy. Then, in her office, strange and threatening messages begin to appear on her computer, summoning her to bizarre sexual liaisons with men she never even sees. Gifts arrive - instruments of pleasure and pain. And unable, or unwilling, to resist, she is gradually drawn from the normality of married life into a world where there are no secrets, where her every desire is known - and fulfilled.