Mr Conway has been described by Mr Trump as “nasty” and even supported Joe Biden in the 2020 election.
Ms Conway claims in her new book Here’s The Deal that most of her husband’s tweets came when he was staying away from his family at their home in New Jersey.
“The numbers don’t lie. During this time, the frequency and ferocity of his tweets accelerated. Clearly he was cheating by tweeting. I was having a hard time competing with his new fling,” she wrote.
“I had already said publicly what I’d said privately to George: that his daily deluge of insults-by-tweet against my boss — or, as he put it sometimes, ‘the people in the White House’ — violated our marriage vows to ‘love, honor, and cherish’ each other.
“Those vows, of course, do not mean we must agree about politics or policies or even the president. In our democracy, as in our marriage, George was free to disagree, even if it meant a complete 180 from his active support for Trump-Pence–My Wife–2016 and a whiplash change in character from privately brilliant to publicly bombastic.”
Ms Conway wrote that she had a matter-of-fact response to her husband’s tweets.
“‘Whoop-de-do, George!’ I said to him. ‘You are one of millions of people who don’t like the president. Congrats.’”
And she added: “On one side was my marriage and my husband. On the other was my job and my boss. George was mixing the two of them in a highly combustible manner.
“I was able to keep these things separate and in perspective. George should have, too, but it seemed the flood of reaction and attention he was receiving was magnetic and irresistible.”