Hollywood icon Robert Wagner still carries the burden of guilt for his wife Natalie Wood's tragic and unexplained death, despite insisting he didn’t kill her. Wood disappeared from a yacht they were sailing in over Thanksgiving in 1981, while Wagner rowed with fellow actor Christopher Walken. Her body was pulled from the sea off the coast of California the next day. Both Wagner and Walken were rumored to have been involved in her death, but Wagner is convinced she fell while attempting to re-tie a dingy that had come loose and was banging against the side of the yacht.But the 78-year-old actor still feels very responsible, because he didn’t save her. He says, "I do feel guilty. I feel when you’re married to someone you’re responsible for them. I’ve gone over it a million times in my lifetime. But it’s not if, it’s what is. It happened." Wagner discusses his relationship with Wood, and other loves including Barbara Stanwyck and Liz Taylor in his memoir Pieces Of My Life, which hit stores yesterday.