The day was hot and clear in the morning, but by noon the clouds had pushed up out of the west rolling a little sultry air before them. Ennis, wearing his best shirt, white with wide black stripes, didn't know what time Jack would get there and so had taken the day off, paced back and forth, looking down into a street pale with dust. Alma was saying something about taking his friend to the Knife & Fork for supper instead of cooking it was so hot, if they could get a baby-sitter, but Ennis said more likely he'd just go out with Jack and get drunk. Jack was not a restaurant type, he said, thinking of the dirty spoons sticking out of the cans of cold beans balanced on the log.
The above takes place before Jack arrives in Riverton.
Alma, in the original story, doesn't invite Jack in for anything. She has no idea as to what kind of relationship Ennis has had with Jack in the first place.
In fact, from the way that I read the story, Alma did notice that very tall Ennis was hugging a person on the upstairs landing outside their apartment door; but, she did not see him kissing Jack at all.
And, I believe the reason after their divorce where she referred to Jack Twist as "Jack Nasty" is that she was guessing that Ennis and Jack had not gone camping at all but were chasing after other women or doing something else which was not right.
from the story:
They seized each other by the shoulders, hugged mightily, squeezing the breath out of each other, saying, son of a bitch, son of a bitch, then, and easily as the right key turns the lock tumblers, their mouths came together, and hard, Jack's big teeth bringing blood, his hat falling to the floor, stubble rasping, wet saliva welling, [i
]and the door opening and Alma looking out for a few seconds at Ennis's straining shoulders and shutting the door again and still they clinched[/i], pressing chest and groin and thigh and leg together, treading on each other's toes until they pulled apart to breathe and Ennis, not big on endearments, said what he said to his horses and daughters, little darlin.
I think that line indicates she saw them.
