At the Thanksgiving dinner, the jig was up, Alma let Ennis know she knew what was going on, as ugly as it was the truth came out. What was going on in Ennis's mind? We know his violent streak came out, he grabs Alma's arm, rushed out of the house, runs to a bar, gets into a fight. His was found out, he was enraged, but not really knowing how it effected him after that, we do know he asked Jack if Lureen pick up any signs, was he going deeper into himself?
We see how he was loved, Alma still loved him, Jack will never stop loving him. Alma moved on, Jack stayed with him, and he still had a relationship with his kids, if Alma wanted to be a real b@#ch about the way her life turned out, she would have used the kids as a weapon, which is not out of the question, she didn't. Alma, Jr. was testament to that.
Ennis ability to still be loved, is one of saddest part of the story, he was totally unaware.