I think the circumstances of given place and time are very important to Alma's reaction. Not only the men, but also the women were expected to marry and raise children (even more than the men). A marriage was often the only chance to leave the own parent's house for a woman. Many women took not whom they loved, but whom they were able to "get" and whom seemed to be not a too bad choice.
Most of the (now elder) women in my family did not marry out of romantic love, but:
- to be provided/cared for (?right expression? - hope you get what I mean) in a social and monetary way
- to not end as a old damsel
- to be able to lead an adult life away from their parents
- because they were pregnant
It was like "you take what you can get and try to make the best out of it".
And after the choice was made once, they had to stand it. No matter whether the husband was an alcoholic who wasted all the money on drink, beat her and/or the children, committed adultery, and so on.
I think Alma, too, tried to make the best out of her situation. She tried to stand her life with Ennis as it was, because at first she saw not other possibility and she was raised to endure it. But as the years went by, the times changed. To leave a husband was no longer impossible and Monroe was waiting in the wings.
And for the OP question: what I would have done if I was Alma? Only thing I know for sure is that I would not have kept silent. Never. This is not in my character. I would have confronted him as soon as he got back from their first trip. Maybe I would have gone along with the social pressure and let the marriage go on (in the sixties whith said circumstances), as a sham marriage. But internally I would have made things very clear.
I hope I would have had the courage to end the marriage years earlier than Alma did. But I don't know for sure.
