I write a lot about how entrepreneurship complicates relationships and even drives couples apart. Sometimes, though, it binds them closer. When the venture serves a larger purpose, through either its core business or philanthropy, spouses who may feel ambivalent about company building (isn't there a less-consuming way to make money?) suddenly get it. Sometimes, they become part of it. And that shared passion -- often more powerful than the shared hobbies that marriage counselors recommend -- can translate into greater passion for each other.

When I met my husband, in 1984, I was managing an organic farm. Gary and his partner, Samuel Kaymen, had just launched Stonyfield, the organic yogurt company. Our idea of fun was making compost together. I appreciated that Gary saw himself as an educator and each little cup as an opportunity to teach people about the importance of organics. But as we hemorrhaged cash for nine years, our small attempt to change the world began to seem delusional. That we labored on behalf of a mission we both cared about made the sacrifice tolerable; I doubt I would have lasted long had we been cranking out Fritos instead. But eventually, although I still supported the cause, I felt disconnected from the company itself.

In recent years, however, I've bonded again with the business. The catalyst has been Stonyfield's philanthropic outreach. Its charitable arm, Profits for the Planet, has supported several causes about which I care deeply, including posttreatment cancer care and restoration of an agricultural building at a Shaker museum. And several years ago, Gary and I together created a loan fund to help New Hampshire dairy farmers through the high costs of transitioning to organic. I personally brought Gary into these and other projects that dovetailed his business mission with my interests. I now influence the company in ways that fulfill me, as opposed to the any-warm-body-will-do kinds of tasks I performed in the early days. And for the first time, I feel truly connected to Gary's work and consequently more tolerant of his frequent absences and distractions.

Something similar happened to Jill Kearney, a professional writer. Jill had no affinity for business when she married Stephen McDonnell, founder of the natural meat company Applegate Farms. "I didn't get the vision and the drive," she told me. "If you're already making money selling X, why do you need to sell 2X?" At first, Jill believed she had nothing to contribute. Eventually, she started writing promotional material and "romance copy" for the products, becoming what she calls a "published pot pie poet." As she worked in the company, Jill began to see the potential for creativity in business and to consider how Steve might apply his abilities to problems outside Applegate.

Then, in 2005, the couple's daughter, 13 at the time, traveled to a remote village in Ecuador as an exchange student. Nora McDonnell's host family was part of a community of subsistence farmers who sold cacao beans. Most of the profits had gone to middlemen until an American researcher helped the farmers form a cooperative to buy the beans and fund the creation of a value-added product: chocolate bars. But the cooperative needed more markets. Jill's interest was piqued, and she and Steve flew down to Ecuador to meet with the farmers. "Afterward, I joked with Stephen, 'If you don't help them, I'm going to divorce you,' " recalls Jill. Steve says, "When Jill has that level of conviction, I respond." So he created a for-profit entity in the United States to sell the chocolate, under the brand name Kallari, and loaned it money. Jill researched how to set up the company and do business in another country, and she applied her writing and art skills to Kallari's packaging design. The farmers now receive a much higher price for their beans, and the profits -- when there are profits -- will flow back to the cooperative to pay for health and education projects. Steve and Jill are in the process of passing control of the company to the cooperative.

A few arguments over process cropped up during the start-up. But those marital tensions were tiny compared with the salutary effects of building something together. Jill loved watching Steve focus his entrepreneurial intensity on a project that did not contribute to their personal bottom line. For the first time, she truly appreciated his business skills. "It's no accident that Steve is successful," Jill told me with fresh pride. "He's detail oriented and extremely tough." Kallari became "an unexpected thrill in my life," Jill said. "We definitely grew into this together. In the early part of our marriage, Stephen's work was the villain. Not anymore."

Perhaps more profoundly, the two discovered they were compatible professionally as well as personally. While working on Kallari, Steve saw how Jill could be more useful to Applegate. And Jill realized that she had a lot to contribute. "Our work at Applegate became a more creative collaboration as a result," said Jill. In the past few years, she has offered marketing ideas, helped Steve think through critical business decisions, and joined the Applegate board.

In some cases, a spouse who helps with company mission winds up going all in. Sheila Hollender gave up her legal practice in New York to move to Vermont, where her husband, Jeffrey Hollender, was building Seventh Generation, the natural home-care products company. Her career upended, Sheila joined Seventh Generation's board and became the buyer for its catalog. But when the catalog business was sold, she said, "there was no place for me in the company."

At about that time, some of Sheila's good friends were receiving cancer diagnoses, and Sheila was growing concerned about the environment's effect on women's health. That became her cause, and she realized her husband's business provided a powerful platform. In 2005, she began pushing senior management to develop organic feminine-care products.

The male-dominated senior management team (there was only one woman at the time) was skeptical. But Sheila argued forcefully that the move would both advance Seventh Generation's mission and enhance its bottom line. "Ninety percent of our customers are women," she told me. At first, Jeffrey was leery of Sheila's involvement, concerned his employees might think he was making decisions for personal rather than business reasons. But over time, he became her greatest champion. Sheila joined the company full time this year, to promote the feminine-care line, which is growing twice as fast as the business overall. "I'm grateful that I could use this company that I've supported for 25 years to further my own passions," Sheila says. Sheila's work at Seventh Generation, Jeffrey told me, has deepened his appreciation and respect for her opinions, ideas, and intuition.

Applegate and Seventh Generation -- like Stonyfield -- are good, socially responsible companies. Yet for Jill, Sheila, and me, that wasn't enough to compensate for the perpetual strain they placed on our family lives. Now, however, those companies -- once antagonists to intimacy -- make it possible for us to spend more time with our spouses and to enjoy our spouses in new ways. For me, it's like making compost with Gary again: layering our mutual talents, interests, and concerns and watering thoroughly with our organizational skills and drive. The result is a rich and fertile ground in which our marriage can thrive.

Meg Cadoux Hirshberg (mhirshberg@inc.com) is married to Gary Hirshberg, president and CEO of Stonyfield Yogurt. She writes a regular column about the impact of entrepreneurial businesses on families.