Ennis, as it was stated earlier was pretty complicated guy. Trying to live his life, appearing conventional, loving Jack on the "down low", and thinking this all he could expect. No matter Ennis's "low startle" point, not one time did he ever stop answering Jack's call to him. Alma or Cassie couldn't quiet the need he had that was only Jack's. Ennis actively defends Jack against Alma, the truth known he never stops seeing Jack. He sacrificed that one good paying job, so he could at any moment be with him, and didn't understand why Jack turns on him.
Ennis handles things his own way indeed. The "Earl and Rich" world, society, was what he try to protect both of them from. But Jack himself, his commitment, his love, his body, was one thing that Ennis had a fear and great need for, but doubted that Jack had the same need for him. He could kill Jack if ever found out that Jack would give himself to anyone else, or even think of leaving him. But what could he do really? No matter how hard Jack tried, or could have tried, talk to him, pushed him, stood on his head and whistle "Dixie", that wouldn't have been enough. For Ennis the only way for him to understand that they were OK, was something he had to discover for himself, and understand for himself.
For Ennis it was "Will you leave me too?" so many in his life left him already.
Just a thought.