Boy = Madness?

I posted this as a reply on this board already but I wondered if anyone else saw the movie in the way that I did.

My first impression was that he was supposed to be madness/insanity. In the dream he said she knew who he was and that he'd never left. At another point she tells him that she had lost her mind after college. I thought those two parts were related. I thought maybe up to her death we were seeing what she, a woman who was loosing her mind again, thought was happening. Also, towards the ending David discards some/all? of his clothing, his wedding ring, and his watch, before getting out of the boat and swimming (I assume) to the house. To me, it seemed like he was going to kill himself (like he really had loved his wife and was sad that she'd committed suicide). I didn't really get the impression that either man was gay ... to me it was more like the younger man was greeting David, as if David is going mad now. But maybe I was way off.