Through the quiet agony of the years of his marriage, there had been one thought which he would not permit himself to consider; the thought of infidelity.
He remembered her hammering derision of his work, his mills, his Metal, his success, he remembered her desire to see him drunk, just once, her attempts to push him into infidelity, her pleasure at the thought that he had fallen to the level of some sordid romance, her terror on discovering that that romance had been an attainment, not a degradation.
There are no more uses of "infidelity" in the book.
Show samples from other sources
The candidate was accused of marital infidelity.
I forgive his infidelity which I have reason to believe he also regrets...