JACK: But beats workin' for my old man. Can't please my old man, no way.
Way before we meet Jack's dad, Jack tells us that he has a poor relationship with him.
ENNIS: My dad, he was a fine roper. Didn't rodeo much, though. He thought rodeo cowboys was all f***-ups.
Ennis's relationship with his dad seems similar to Jack's relationship with his. This gives the two men something in common to commiserate about.
ALMA: I know you'd like it too. Real home, other kids for the girls to play with. Not so lonely, like you were raised. You don't want it to be so lonely, do you?
Both Ennis and Jack want a family life different than the one they were raised.
ENNIS: Hey, you might want to keep it down, I got two little girls here.
Ennis believes that being a father means beating people up when they offend his sensibilities. He must have learned that from his own dad.
JACK'S FATHER-IN-LAW: He's the spittin' image of his grandpa. Isn't he the spittin' image of his grandpa?
Jack does not have a good relationship with his new family. In fact, his relationship with his father-in-law isn't dissimilar from his relationship with his own father. Jack's father-in-law depersonalizes him by calling him "Rodeo" instead of by his actual name.
ENNIS: I doubt there's nothin' we can do. I'm stuck with what I got here. Makin' a livin's about all I got time for now.
Ennis's family wouldn't want to hear them being described as something he is "stuck with." But this honest line shows us that Ennis somewhat regrets having a traditional family What he really wants is a life with Jack, but he lets society's prejudices prevent him from having that.
ENNIS: No, I told you, it ain't gonna be that way. You know, you got your wife and baby in Texas, and you know, I got my life in Riverton.
JACK: Is that so? You and Alma, that's a life?
ENNIS: Now you shut up about Alma. This ain't her fault. The bottom line is, we're around each other and this thing grabs hold of us again, the wrong place, in the wrong time, we're dead.
This exchange is almost a 180 from the "stuck with" quote of before. By this point, Ennis has convinced himself that he is happy with Alma because he has no other alternative.
ENNIS: If you don't want no more of my kids, I'll be happy to leave you alone.
ALMA: I'd have 'em if you'd support 'em.
JUDGE: Defendant is ordered to pay child support to plaintiff in the sum of $125 per month, for each of the minor children, until they reach the age of eighteen years. Divorce granted, this 6th day of November, 1975.
Ennis and Alma's divorce seems to happen fast, but it was brewing for years. Alma wants a family more than anything else…one that doesn't include a husband who is having an affair with another man. She just needs a better excuse to divorce him, because Ennis doesn't know that Alma knows his secret.
JACK: Now you sit down, you old son of a b****! This is my house, this is my child, and you are my guest! Now you sit down, before I knock your ignorant ass into next week.
Jack yelling at his father-in-law is cathartic for Jack, because this is probably something Jack has always wanted to say to his own father. This "kills" Jack's father, metaphorically, because it puts his father issues to rest, and it's the last we see of Jack's father-in-law. Even Lureen likes seeing her own dad get told off by her husband.
ALMA: You ought to get married again, Ennis. Me and the girls worry about you bein' alone so much.
In the 1960's and 1970's, having a family was the ultimate goal, so Alma puts this pressure on Ennis to get remarried, without considering that he might not want that.