I find the idea of Ennis being in a "war zone" interesting. Ennis described to Jack how his daily life was like navigating thru a mine field: "Ever go out on the pavement and see the people and think that they all know?" he asked Jack. Ennis was concerned for his physical safety, afraid he'd be ambushed at some unsuspecting time and strung up just like one of those two old birds he saw when he was nine.
I also think the idea of Ennis and Jack being the same is true in a way. Ennis and Jack were complementary, like the two sides of a coin, or like yin and yang. They grew up in opposite corners of Wyoming and, altho they had each endured hardships and were inured to the stoic life, they reacted to life's adversities in opposite ways, Ennis withdrawing to within, Jack reaching out.
The only thing I know about the greyhound bus, though, is that Ennis was eating pie in the station when Cassie came upon him!
Now, back to the rejecting...Ennis in the story even rejected his daughters after the divorce. Although he continued to pay child support.
War Zone Analogies -
The words that Ennis used in his last scene with Jack were not "navigating a mine field", however, that may a reasonable interpretation of his life -
but then maybe it isn't a reasonable interpretation.
I don't think that Ennis was living in an impossible situation for him, he had resigned himself to his limited small life, and he envisioned no other. I think he was economically challenged, and that is a large portion of his frustration in his last meeting with Jack, and he was frustrated with Jack for bringing up yet again the idea of them living together. Ennis just wanted a peaceful existence with a certain amount of limited contact with Jack, but I am not convinced that even if Ennis were less economically challenged he would have agreed to live with Jack. In a way, Ennis would have viewed living with Jack as trading one whining, dissatisfied partner (Alma) for another whining, dissatisfied partner - and I think that Ennis feared that. Ennis liked his solitary life out on the range with the animals as his only companions, he was a distinctly inwardly driven person. And I think to the point of it being a pathology, but that was Ennis.
As to the business of Ennis rejecting people, yes, he wanted contact with people only up to a certain point. I think that it is overlooked that this trait may be not only a part of his difficult relationship with Jack but a part of his basic nature. He was probably basically an antisocial person. There are lots of social recluses in the world, mostly they do no harm, they just keep to themselves and want no "help" or "redemption".
Do I think that Ennis had a mildly pathological personality? yes to a degree?
Do I think that Jack was better adjusted? Mostly I do.
In a sense Ennis was incompatible for either Jack or Cassie, and to a large degree he was also incompatible with Alma. But, I find it interesting that the one person who spent the most time, hung on to him the longest, was Alma. In the 12 or so years they were married, they were together most of that time, except for Ennis's time on the range and with Jack. Jack and Ennis were together physically about a total of one year if you add up all their time spent in each others company. Cassie was together physically with Ennis about probably the same amount of time. I suspect that if Jack had moved in with Ennis, he would have left him within a year, and the same with Cassie. And Ennis had to understand deep down inside that he was better off keeping Jack and Cassie at arms length.
The more interesting question to me is : why did Jack hold on so tight and never gave up on Ennis when they really weren't that compatable emotionally? Perhaps Jack could envision no better life either.
