My secret history / Paul Theroux.

Enhanced descriptions from Syndetics:

Brilliantly written, erotically charged, My Secret History is Paul Theroux's tour de force. It is the story of Andre Parent, a writer, a world traveller, a lover of every kind of woman he chances to meet in a life as varied as a man can lead.

It begins with his days as a Massachusetts altar boy, when his first furtive sexual encounter introduces him to the thrills of leading a double life. As a teenaged lifeguard, Andre finds himself caught between the attentions of a beautiful young student and an amorous older woman. Soon he is in Africa, where the local women are numerous, easy, and free. And as the boy becomes a man he turns his attention to writing, which brings him fame, and a wife, who may finally cause him to know himself.

But not before he sets up his most dangerous secret life, one that any man might envy, but that could cost Andre Parent the delicate balance that makes him who he is.