I'm trying to track down the title of one of Bradbury's non-science fiction short stories. I read it over twenty years ago - I can't even remember the title of the book.
It was about a man and a woman; two very affluent, very spoiled people who fall in love, use and abuse each other, fell apart and came back together again. I remember a passage in which they are on a beach and there is a reference to something offshore, moving below the surface. If anyone can supply me with the title of this short story, I would be grateful.

RonM

I'm guessing this may be it, but only because your description kinda sounds like it... so I'm linking the info here...
http://immersion.raybradbury.ru/english/1/1/