"There is nothing new about this idea," Coontz told ABCNews.com. "Women have been marrying for mercenary reasons for most of history. They had to, because they couldn't support themselves."
She said that as late as 1967, women routinely considered marrying a man they didn't love "if he met the financial criteria."
For thousands of years, marriage was based on political and economic convenience for both men and women.
"Until the 18th century the biggest infusion of cash until marriage was death and an inheritance," said Coontz. Next was the dowry.
"Families were interested in the connections to in-laws to improve their financial interests," she said.
But as the middle class emerged and men could support themselves rather than depend upon an inheritance, they became "the most exuberantly romantic," she said.
"Women who were totally dependent and legally subordinate said things in their diaries like, "Caution: My heart inclines to Harry, but I can't take that risk."
By the mid 20th century, modern attitudes gave men and women equality to choose a mate, but not economic equality.
Men expect power because they make more money and women "trade services for deference," Coontz said. "This has created an unstable situation."
The best hope for a stable and satisfying marriage is one where both husband and wife share the bread-winning, child care and housework, according to Coontz.
"Women mostly say it is less important to have a man earn a lot of money than a man who can communicate and share his feelings," she said. "And that doesn't mean they want to marry a deadbeat."
The book's authors agree that economic equality is important.
They argue that women can't earn as much as men, especially after having children, and if they do marry well, and then split, they are shortchanged by divorce, both professionally and financially.
The book cites research by Professor Stephen Jenkins, director of the Institute for Social and Economic Research, who found that five years after divorce, men were 25 percent richer, whereas women still had less money than they did pre-split; and that 31 percent of mothers received no support no payment for children.
Women face the pressure to do it all -- raise children, earn a decent salary and be a hot sexpot in bed.
And, the authors note from personal experience that 50 percent of all marriages are doomed to failure.
"If falling in love is a valid reason to get married, then falling out of love is a reason for divorce," said Ford, whose husband left her two years ago to raise their now 8-year-old son, motivating her to write the book.
Ford's enthusiasm for the topic was also fueled by a younger sister who graduated from college "looking for love" and ended up with "slacker guys who don't pay the rent."
Her co-author, Drake, left her husband, because he had no concern for the couple's finances. She is now remarried with two children.
A good marriage, they both say, is an economic partnership. And research shows that if a couple stays together long enough, the passionate love will reignite.
Such was case with one blogger on the Web site Urban Baby who said her best friend had always dated "rocker guys" but, instead, married a Jewish MBA consultant.
"She admits that he is not as sexy, interesting or thrilling as her past boys," she wrote. "But he is understanding and kind and super intelligent. I 'm sure that loft in Tribeca didn't hurt either."