While this may be a story about the love between Ennis and Jack, Ennis is our main man. Why's that? Well, to out it frankly, it's because he's the only one of the two main characters who isn't dead at the end of the story.
And that's kind of the point. Sure, he and Jack are both "high school dropout country boys with no prospects, brought up to hard work and privation, both rough-mannered, rough-spoken, inured to the stoic life." (3) Those surface similarities, however, hide deep-set differences that explain why Ennis ends the story alive and Jack doesn't.
Ennis is the quiet one, the cautious one, the one who would rather keep quiet and stay unobtrusive than yell "I love this man!" and face the consequences. In fact, he's the kind of guy who'd rather not talk about anything even when it's staring him in the face.
For example, when Alma catches Ennis and Jack in a fierce embrace, he pretty much pretends it didn't happen. "'Ennis – ' said Alma in her misery voice, but that didn't slow him down on the stairs and he called back, 'Alma, you want smokes there's some in the pocket a my blue shirt in the bedroom.'" (57). Yeah, this is not a man who wears his heart on his sleeve or likes to talk out his problems.
It gets worse. After he fights with Alma on Thanksgiving, he pretty much just leaves and lets other people do the emotional heavy lifting: "He didn't try to see his girls for a long time, figuring they would look him up when they got the sense and years to move out from Alma." (93). Poor Ennis is not exactly a model of emotional maturity. This kind of drives Jack nuts, but Ennis is undaunted. "If you can't fix it you got a stand it," he tells Jack (78), which pretty much means "shut up and keep your head down."
There's a price for this, of course. Ennis's cork is wedged in a little tight. His emotions run very deep and he isn't always aware of them. When he first leaves Jack after Brokeback, for example, he "felt like someone was pulling his guts out hand over hand a yard at a time. He stopped at the side of the road and, in the whirling new snow, tried to puke but nothing came up. He felt about as bad as he ever had and it took a long time for the feeling to wear off" (38). Sure, these are physical symptoms we're talking about, but their cause is emotional. It's quite possible that Ennis loves Jack, he just doesn't know it, let alone how to deal.
Naturally, when those emotions do come out, it's a little loud and scary. When he fights with Alma at Thanksgiving, "He seized her wrist; tears sprang and rolled, a dish clattered" (89). He's a powerful man with some powerful feelings, and Proulx never lets us forget it. That makes those moments where Ennis's emotions do show all the more powerful.
Ennis's inability to express himself is possibly the most tragic thing about "Brokeback Mountain." In a sick way, it pays off because he's able to keep his desires in check. That means he can keep a low profile and avoid a horrible fate like the one Jack meets. But it also means that he's left alone in a trailer with only a couple of bloody shirts for company. Poor Ennis.
But that's more than just a sad ending for a sad story. In fact, Ennis's quiet stoicism points to one of the story's central themes: the effect of prejudice and intolerance on a person's private life. In many ways, while Jack might dream about the possibilities of a life together, Ennis knows it could never work because the world—or at least their world—will never accept them.
He knows he loves Jack, but he also knows that their love doesn't fit what society allows. And as the end of the story puts it, "There was some open space between what he knew and what he tried to believe, but nothing could be done about it, and if you can't fix it you've got to stand it" (159).