I like this discussion condisering Ennis and his "denial" (or lack thereof) on Brokeback vs. life-down-from-the-mountain. I've always felt like we see Ennis evolve throughout the film. And sometimes he back slides and sometimes he seems to be taking steps (even baby steps forward). And sometimes this is a confusing process. The best example is probably the prayer of thanks camping trip where he seems completely relaxed, happy and willing to "submit to the relationship" (a phrase I remember someone once using to describe his demeanor here...) but then whiplash-fast he changes... sits up, puts the rigid hat on, adopts closed-in body language, tells the Earl story, etc. So in a way I feel like we're seeing a step forward and a step back here by Ennis.
But, what I really want to say is that I think there are 3 main phases of Ennis. Brokeback Ennis (free from society), Riverton Ennis (having to deal with society, but Jack is still alive, and available and the comfort that he runs to a few times a year) and then Ennis Post-Jack. I think the Ennis we see following Jack's death is a hugely different character in many ways. His evolution is lightning fast.