Just one last quote from the interview:
Annie Proulx: "Brokeback Mountain itself, the idea of using the mountain as--what they call in science fiction a wormhole, where two characters go in and they come out differently--and this was a thing I wanted to play with from the beginning, and I think it worked."
...
"when I was working on the story... I was near tears myself many, many, many times--which I found a bit frightening. And yet I never could cry. And in eight years I haven't been able to., but I have been thinking that one day I will be able to. I'll get around to it. But I can't right now. The whole question of a large love that comes out of nowhere and just slams you to your knees--happens."