The Birthday Present by Barbara Vine

It shouldn't have been a big deal.  Ivor Tesham is young, wealthy and a rising member of his party in England.  Hebe is his married lover, not morally right but a commonplace sin.  Hebe is willing to fulfill Ivor's fantasies, and for his birthday, they set up an elaborate game.  She will be taken from the street by two armed men, bundled into their limo, and delivered bound and gagged to Ivor for the night's games.

But things go horribly wrong.  There is a wreck and Hebe and one of the men are killed, the other man horribly injured.  The press gets the story, but believes that it was a real kidnapping attempt, one on the famous wife of a wealthy man.  Ivor's name never comes up, and he doesn't come forward since he knows it will end his political career.

The story dies down since the participants are dead as far as the press knows.  Ivor starts to feel safe, but there are still people who know.  Like the man who survived and his family.  The girlfriend of the other man.  Hebe's friend who she used to give her alibis to deceive her husband.  As the weeks and then months and years go by, Ivor learns to live with the past, never sure when and where it will rear it's ugly head, taking him and all he has down with a resounding explosion.

Barbara Vine is Ruth Rendell's alternate name, and her mysteries written as Vine tend to be more psychological than her other novels.  There is always an offbeat twist, and she outlines the events in such a way that the strange happenings seem to almost be the only logical outcome.  This book is recommended for mystery lovers.