So Much Blue by Percival Everett

Kevin Pace is working on a painting that he won't allow anyone to see: not his children; not his best friend, Richard; not even his wife, Linda. The painting is a canvas of twelve feet by twenty-one feet and three inches, covered entirely in shades of blue.

It may be his masterpiece or it may not; he doesn't know, nor does he particularly care. What Kevin does care about are the events of the past: the affair he had with a young artist in Paris ten years ago and, further back, his journey to an El Salvador on the brink of war to retrieve Richard’s drug-dealing brother.
 
So Much Blue is a brilliant examination of how the past collides with present, and the secrets we keep from even ourselves.