Secrets

During chapter 5, as Billy is honeymooning with his wife Valencia, "'...I get a funny feeling you're just full of secrets.' 'I'm not,'  said Billy. This was a lie, of course. He hadn't told anybody about the time-traveling he'd done, about Tralfamadore and so on." (Vonnegut, 121). I wonder why Billy would not share any of the strange things he has experienced. You would think he would feel the need to tell someone, especially his wife. If you were in Billy's position would you tell anyone, or keep it to yourself?