During the perilous early years of Stonyfield Farm, I didn't work outside the home. My husband, Gary, and I managed to live on his meager income. But many spouses of entrepreneurs are their families' sole financial support. While their entrepreneurial mates are off pursuing a risky vision, these forced-to-be-practical husbands and wives work as hard as they can in the most secure jobs they can find so that they and their loved ones don't have to go live in a tent. People can get tetchy in arrangements like that, and not just because they're stretched for cash.

In these situations, the family endures the stress of two working parents but must survive on the income of one. Making matters worse, part of that income frequently gets shoveled into the ravening maw of the business. It's probably not fair to compare such situations to the melodramatic cliché of long-suffering wives surrendering their paychecks to ne'er-do-well mates who squander the money on drink or drugs. That would imply entrepreneurship is expensive and addicting and may end badly. And I, of course, would never suggest that.

Normally, when only one household head is earning a wage, the other takes up the slack at home. But company founders are often busier and more preoccupied than are their salaried mates, who consequently reap no stay-at-home-spouse premium. Sole-supporting spouses also fear that their sacrifices may come to nothing. If a husband plays breadwinner while his wife pursues higher education, brighter postgraduation job prospects will likely reward both. The same is true if the wife is an entrepreneur whose company succeeds. But that's a much bigger if, and the timeline is unpredictable.

Many sole breadwinners report feeling professionally trapped and jealous that their entrepreneur-spouses are able to chase their dreams. I spoke with a former investment banker who had quit her job to launch a company. One day, her husband, a physician, called from the office to announce that he had a buyer for his practice and was considering selling. "I freaked out," she said. Turns out the husband wasn't serious. But he wanted her to understand that her decision to launch a business had left him feeling cornered, forced to work longer and harder than he might have preferred.

Gender stereotypes can also ramp up guilt and resentment, even in 2012. Some male entrepreneurs worry that they're not fulfilling their traditional bringers-home-of-bacon roles. One told me he was failing at being "a provider and protector." A woman whose husband is an entrepreneur said that even though she has the job and the credit cards, he grabs the check at restaurants, ashamed that the waitress will see who pays the bills. "Sometimes I'd look at him and think, Wow, you are useless financially," she told me. "That is a horrible, destructive thought."

Matters get worse when the spouse supports not just the family but also the business. Though most couples make early commitments to keep business finances separate from the family's accounts, young companies are like baby birds with gawping beaks, always needing to be fed. When Andrea Mealey's husband, Jim, started a company that rehabbed houses, she used some of her salary as a Boston attorney to pay for equipment, subcontractors, and other business expenses. "For several years, 'B of A' meant 'Bank of Andrea,' " she told me. "Jim said he was happy not to be 'some wage slave working for the Man.' But the fact is that his decision to start a company forced me to be a wage slave, and much of what I earned went right into the company."

In these situations, joint checking accounts become hubs of domestic drama. The spouse deposits; the entrepreneur withdraws; and then the spouse withdraws from the entrepreneur in anger for not being consulted. Or the spouse demands a say in company expenditures, irritating the entrepreneur, who resents being slowed down or second-guessed. "Jim hated having someone to answer to," said Andrea, who insisted on oversight of the rehab company's spending. "It took me a long time to say, 'You also have to answer to me.' " (Jim has since dissolved his company and now works as an economist.)

Perhaps even more debilitating for the marriage than resentment is guilt—even fear. Entrepreneurs know they are indebted to financially supportive spouses. A sense of obligation naturally arises from the request, "Sweetie, could you start working overtime so I can realize my life's dream?" And the spouse has the option of removing support at any time. One entrepreneur told me that she became so desperate to remain in her husband's good graces that she traveled less, cooked more, and rarely challenged him on family issues, such as how he disciplined the kids. Anxious to keep his salary flowing to her new venture, she tried to make her husband happier in other ways, too—becoming, in her words, more "accommodating" in the bedroom.

And, of course, every penny diverted to the business is diverted away from the family. That can lead to queasy confrontations, such as one described by Kris Boesch, founder of Choose People, a Colorado-based company that helps businesses improve their cultures. Kris reported feeling vexed that her husband would cheerfully spend his income on art school for their child but wouldn't pay for an airline ticket to a convention that was important for her business. "I asked him why he was willing to help with our child's dream but not mine," she said. "When he placed limits on how much I could use for the business, I wondered where that limitation was coming from. Was it financially based or just what he was arbitrarily willing to do?"

In time, though, Kris came to see things differently. She realized her husband was putting money into the company as an investment, not as a favor to her. That insight, in turn, made her more hardheaded about the business. She began focusing more on closing sales than on marketing and became a frugal bootstrapper, staying with friends when she traveled on business trips. "I had been giving my company a longer runway than it needed," she said. "I feel much more accountable now. It's no coincidence that I'm at breakeven." Kris's shift in perspective improved not only her company but also her marriage. "We're now on the same team," she told me. "We're both investors. Of course, it also helps that I no longer need his financial support."

Like Kris and her husband, couples can drain much of the emotion from sole-support situations by treating the business as a shared investment and setting expectations and ground rules up front. Long-horizon, detailed family budgets are critical. And spouses need assurance that the I-give-the-company-takes dynamic will eventually reverse. For several years, Jacquelyn Draplin's Web-analytics job has supported her husband, Justin, and their young daughter while Justin and a partner have built PowerCapes, a Livonia, Michigan, company that sells custom superhero costumes. Justin, not surprisingly, wanted to plow everything back into the business. But he agreed that once the company inched into the black, 15 percent of profits would return to the family's personal account. Fifteen percent "may not be much," said Jacquelyn. "But it makes me feel he's putting the family first, not the company."

In the best of all possible worlds, the business thrives and the spouse proudly shares credit. At that point, she is free to take a break, continue her education, or tackle a new, more fulfilling career. She may even choose to start a company. She already knows someone who can help out with the money.