When I moved to Stonyfield Farm in the mid-1980s to live with my then-fiancé, Gary, I immediately went to work in his yogurt business. I worked part time in the office and in sales, reporting to Gary, and part time as a yogurtmaker. At that time, the "factory" consisted of some jury-rigged machines in our barn; turning out good product required improvisation and luck. But my sales job was just as taxing, in personal ways I hadn't anticipated.

I started working for Gary for the same reasons most spouses get swept into entrepreneurial ventures: I was available, capable, and cheap. My role grew out of expediency, not because I possessed any particular skills or an abiding passion for the job. Because my future depended on the company's success, I was certainly dedicated. But Gary and I were not equal partners living a dream of our joint creation. And so we suffered double the stress without enjoying double the personal fulfillment.

Many couples meet on the job, and office anxiety follows them home. But when one spouse goes to work in the other's company, there is no relief in railing against the boss or fantasizing about going elsewhere. Even when one spouse doesn't report to the other, the entrepreneur usually wields implicit authority--not ideal when you're trying to sustain a marriage of equals. The work environment may reveal quirks or irritating habits in both of you that never surfaced in domestic life. The most routine operations can generate a dozen new issues a day on which you disagree. And home ceases to be a sanctuary when dinner-table conversation picks up where the afternoon huddle left off.

Even the way you talk to each other is affected. Michael McMillan, an Inc. reader who works with his wife at their family-owned call center, Answer Center America, described it to me this way: "Problems at work demand yes-or-no solutions, and there's often no time for explanations. You need to keep emotions hidden at the office--you can't personalize disagreements." At home, of course, conversation, compromise, and nuances are important. Everything is personal. Making the shift, from tough and impervious at the office to communicative, open, and sensitive at home, can be challenging for both spouses.

For Gary and me, working together revealed aspects of our personalities that had not emerged in two years of courting. Often when he'd give me instructions on how to handle our clients or suggest travel shortcuts for business trips, he'd talk fast and skip details. He sometimes became impatient with my confusion. For my part, I personalized everything and felt hurt by his occasional abruptness. I was unable to compartmentalize--a critical skill for couples who work together. Unrealistically, I expected that we'd take the time, even during the workday, to solve problems as they arose.

We were often harried and uneasy--a reasonable response to the constantly looming threat of bankruptcy. Our edginess seeped into our home environment--home being about 10 feet from the office. Sometimes after my shift in the yogurt factory, I would meet Gary back in our apartment to make supper. Hairnetted and sweaty from the incubator, I'd fret about our endless production problems and thus further blur the faint boundary between the business and our personal lives. Sitting at the dinner table, we were in no mood to pose that sweet inquiry of the other: "Honey, how was your day?"

One reason spouse-employee arrangements sometimes sour is that so little thought goes into them. New employees are interviewed to assess their skills and interests; their working conditions and responsibilities are defined up front. Spouses, by contrast, may have to alter their shapes to fit whatever hole the company needs filled. Sometimes it's a match: The onetime accounting major takes over the books. Sometimes it's not: I was a literature major who helped with accounts receivable. In situations like ours, subjects such as compensation, flexible hours, and titles are often not raised. How long will the arrangement last? Is the spouse just helping out or putting his or her own aspirations indefinitely on hold?

Then there's the problem of power. Hierarchy at work is unavoidable. Someone has the final say. Established couples may find it easier to prevent those dynamics from contaminating their home lives. But when authority flows in one direction all day, it doesn't reverse course easily. One long-married Inc. reader wrote me: "My wife is the boss at home, too. I now feel like I work for her 24 hours a day."

Often, married couples imagine they're immune, because they know each other so well. Sometimes, though, they only think they do. When one friend of mine joined his wife in her business, he discovered that "she wasn't just a witty, sharp-tongued, funny woman--she was actually mean and abusive. We stopped liking each other." The couple eventually divorced.

On the flip side, others told me they came to respect their spouses more after observing them on the job, where they appeared better organized, more focused, or more dynamic than at home. Working with Gary, I marveled at his creativity, and his optimism and calm in the face of disaster.

Then there's the problem of power. Hierarchy at work is unavoidable. Someone has the final say.

There are obvious ways to avoid the pitfalls. Establish job definitions and working conditions up front. Reinforce the message to each other--and to everyone else--that you are in this together, pursuing a common goal, even if one of you plots strategy while the other restocks shelves. At home, carve out inviolate time in which office talk is verboten.

Perhaps more important, ensure that the spouse receives the same appreciation and recognition due any talented, hard-working employee. "The gratitude thing is key," said Inc. reader Ginger Molthen, who works with her husband, Tom, in his salsa business, Pepper Dog Specialty Foods. "Otherwise, I feel like, Hey, I don't need this. We've both sacrificed for what he wanted."

After six months or a year, step back to evaluate the arrangement. This isn't a performance review--it's a relationship review, with the option of reconfiguring either spouse's role. You may conclude you're simply not happy working together. But that doesn't mean you shouldn't be together. As Michael McMillan put it, "The most important thing is to commit to saving your personal life before you save your professional life."

Some relationships thrive in the workplace, as couples share highs as well as lows and avoid the long hours of separation typical in entrepreneurial ventures. The intensity of the shared experience can strengthen their bond. They are likely to be able to sympathize with each other's stress and the need to work evenings or answer business calls on weekends. Couples who work together can offer each other wise and informed counsel about business-related problems.

But for Gary and me, those benefits weren't worth the cost. One spring morning, two years after I joined Stonyfield, we had our last business meeting in his office. By mutual agreement, we decided I should leave the company. Our business situation at the time was dire, and when I got pregnant, I became concerned that our chronic, extreme stress would affect the baby's health. Also, we had both learned something important: Though personally compatible, we did not work well together. We chose to protect our relationship, which had existed before the business and which we wanted to exist long after it. We smiled and embraced. I turned on my heel and walked the 10 feet back home.