Monroe is the nice grocery store manager with a desire to supermarket sweep Alma off her feet. When Alma has to take care of her kids at work, and Alma Jr. knocks over a display of condiments, Monroe happily cleans up the mess. He says,
MONROE: Really, Alma, it's okay. I'll get it.
This moment foreshadows Monroe cleaning up the mess of Alma's life. She marries him after divorcing Ennis. And honestly, he seems like a good dude.
The movie contrasts Jack and Monroe in their separate Thanksgiving scenes. Jack carves the turkey with a knife. Monroe uses an electric carving knife, which is intended as a comic, emasculating moment—but it also signals the fact that he's well-off and forward-thinking. (Nothing shouts "the future!" like an electric knife.)
Unlike Ennis, though, Monroe at least has a turkey to carve. Ennis can only sit at the table, no longer a part of the family.