(FORTUNE Small Business) – When Anthony DeHart got married seven years ago--in the midst of building his precision-cutting-tool company, DeHart Tooling Components--he made three mistakes. First, after a romantic wedding in Greece, he whisked his bride off to a honeymoon at...a machine-tool trade show in Germany. Huh? "I actually tried to make vacations out of business trips for the first two years we were married," he says a little sheepishly. "And a new bride is not going to complain about how bored she is, although later my wife, Dottie, got more vocal about it, because she spent so much time sitting around in hotels waiting for me. Big mistake. Now if we take a vacation, we make it a real vacation." His second error? During the first few years he and Dottie were married, he plowed every dime of profit back into his Hickory, N.C., business--"which meant I was financially dependent on her, which was an unfair burden," because she was, in addition to working full-time, raising their first child. "It wasn't good for the marriage to have her shouldering so much of the load," he says now.

And the third mistake? Ah, friends, this one's the real biggie. "I underestimated how much time the business was going to take away from my family," he says. "I was literally never home. Our marriage almost didn't survive. I got to the point where I had to say to her, 'I'll do anything. Just please don't leave.' " The wake-up call came when the DeHarts discovered they were going to have a second child, who is now 5 months old. "We had been growing apart for a long time, but that was when we really had to sit down and say, 'Okay, what are we doing here? Where are we headed?'"

It goes without saying that neither building a business nor sustaining a happy marriage is easy--and trying to do both at once can seem an impossible dream. In fact, to hear some experts tell it, entrepreneurial couples need coping skills that regular people can hardly imagine. "It's like walking the high wire over Niagara Falls. It takes a lot of skill, and you can fall off easily," says Henry Landes, who founded and operates the Delaware Valley Family Business Center in Sellersville, Pa., near Philadelphia. (He runs management workshops and provides an array of counseling and consulting services to family-owned startups.)

A marriage in which the business is the biggest baby, counselor Landes says, "has to be a stronger marriage than most. It needs better communication skills, better conflict-resolution skills, better specific planning skills, and a lot more resilience." Gulp. But, hey, cheer up. It seems that despite the pitfalls, plenty of entrepreneurial couples are meeting that challenge, and that, ironically, the shared struggle of creating a company can make a good established marriage even better.

For one thing, there's no evidence that the divorce rate among business owners is any higher than average (although when entrepreneurs do call it quits, the results can be a bit messier--see box on page 69). Moreover, according to a recent survey by the investment advisory firm Neuberger Berman, 42% of CEOs of fast-growing startups say that running their own companies has had a positive effect on their relationships with spouses or domestic partners. That is significantly higher than the 32% who said business ownership had caused trouble on the home front. The good news, says Kelly Deets Baker, whose husband started a business less than a year into their marriage: "It's been harder for us than I anticipated, but I think it has made our marriage stronger. I think I understand him better than I would otherwise--what stresses him out, what makes him happy --and I think that goes both ways."

Nili Sachs, a marriage counselor in Rockford, Minn., who has worked with hundreds of entrepreneurial couples, believes that business owners may have some distinct advantages when it comes to making a marriage hum. Entrepreneurs are perceived (often accurately) as loners, she notes--but they also have a strong drive to succeed and are skilled at working toward a goal. Any business owner who makes a happy home life a distinct goal, she believes, is quite likely to achieve it.

The obstacles, though, are real. First, keeping a business going (especially in this recession-stressed economy) can soak up every hour there is in a day and then some. "Time is the No. 1 issue," says Rachna Jain, a psychologist in Columbia, Md., who counsels business owners and their better halves. "When you're never around--and even when you are home, you're still thinking about the business--it's easy for a spouse to feel neglected, even jealous. I can't emphasize enough the importance of being aware of this and discussing it honestly before little problems turn into big ones."

One of her clients was the always absent owner of a printing business whose wife was trying to deal with a serious illness. "He felt overwhelmed. She felt abandoned," says Jain. "The marriage very nearly ended." After a few counseling sessions, talking openly about the strains each was suffering, the couple decided to make some changes, including getting part-time help at home until the wife recovered. "But ideally they should have had this discussion sooner, before the marriage was on the brink of collapse. You need to stop the drips before they become a flood," Jain says.

And, ideally, before they wash out your sex life. Aline Zoldbrod, a licensed sex therapist and author in Boston who treats plenty of high-powered tech entrepreneurs with companies on nearby Route 128, describes the most common problem she sees: "The men work all the time, and then when they have a spare moment, they expect spontaneous sex--and are baffled and angry when their wives don't respond." One client, she recalls, "actually sat in my office and shook his finger in his wife's face and shouted at her, 'I work constantly to make all these big deals so you can have all the money you want, so what is your problem?'" (Gee, how romantic.)

"My role is to explain to these husbands that women need time to get back in touch and in tune emotionally before they can feel any real desire to jump into bed," says Zoldbrod. "I urge them to schedule time for their wives--just the two of them, just hanging out in front of the fireplace or going out to a relaxed dinner and a movie." She adds, "It's important to start 'dating' again before too much resentment and hostility have built up, because by then it's too late."

After time and attention (and sex), the most contentious issue entrepreneurial couples face is--you guessed it--money. "One of the hardest things for the spouse of an entrepreneur to take is the huge swings in cash flow," says Deets Baker, whose husband, Bill Baker, co-founded a flavors and fragrances manufacturing company, Flavor Systems International, in Cincinnati. One year the banks called Bill's loans right before Thanksgiving: "We had planned a huge Christmas party, but we canceled that. And Christmas. And our usual New Year's trip. It freaked me out at first." Another time the company gained a big new client, but, says Deets Baker, "when you're putting things in place for the future--hiring people, for instance, to handle a new client even though the client won't be paying you for a while--you're still broke."

But Deets Baker has weathered the toughest early stages so unfazed that she has now quit her job at a high-tech firm to launch her own home-remodeling company, Ridgeland Properties. What helped pull her through? "Bill's always been great about telling me how the business is really going--the good, the bad, and the ugly," she says. "And that honesty was important. If I wasn't going to be able to pay the bills on time one month, I didn't want to hear about it after I thought the check had already been deposited. You need super-open lines of communication."

No question about it: taking out a second mortgage on the house, raiding the family savings, and maxing out the credit cards can raise the stress levels in a marriage, and many entrepreneurs who spoke to FSB for this story said that worry about finances had given their spouses serious pause. Unfortunately anxiety is contagious, especially at such close quarters. When executive coach Rachelle Disbennett-Lee started her executive-coaching firm in Aurora, Colo., she says, "my husband had a lot of fear about my not having a steady income and doing something so risky. His fear created fear within me, and it was all I could do to ignore him and move ahead." As the business grew, she slowly won him over--in fact, he works for her now--but it was a white-knuckle ride. Disbennett-Lee's advice: "Make sure your spouse understands realistically how long it will take before the business will be earning a profit." And then just hang in there and hope that confidence is contagious too.

Couples who are co-founders face even bigger challenges. The National Federation of Independent Business estimates that there are now 1.2 million husband-and-wife teams running companies in the U.S., and that figure includes only businesses that employ others. (If mom-and-pop enterprises with no other workers were included, the number would be far higher.) Yet, as with entrepreneurship generally, starting a business with a spouse is not for the faint-hearted. "I don't think most people who are married to each other should be working together," says Henry Landes. "The criterion I use is: Start with a clean sheet of paper and ask yourself, What do I want and need in a business partner? And would I go into business with this person if I weren't married to him or her?"

Among couples who have taken the plunge, those who are both still speaking to each other and running successful enterprises together seem to follow two rules: First, figure out right at the start who is going to be in charge of what--and then stay out of each other's way. And second, try not to let the business become a round-the-clock obsession. Carve out separate and distinct times to relax and have fun together (and with the kids, if any), even if it's only for a couple of hours a week.

Consider, for instance, Terry and Stella Henry, who started Vista del Sol, a long-term-care and assisted-living facility in Culver City, Calif., 24 years ago--and got married a year later. Stella, an RN with long experience in patient care and quality control, is in charge of dealing with patients, their relatives, and employees; Terry handles the business end, including finance.

"This business has both animate and inanimate parts," says Terry. "She does the former and I do the latter." Their offices are on different floors of the same building. Keeping their separate roles clear is good for both the marriage and the business. Notes Stella: "There are no gray areas, which among other things keeps employees from playing you off against each other. In our own spheres, our decisions are final."

As for the second priority, keeping work and romance from colliding, they're old hands at it. "In the early startup stage, which was very tense, we used to take three-day vacations every three or four months," Terry recalls. "We'd go to Hawaii, do absolutely nothing but relax for 72 hours, then take the red-eye back. People thought we were nuts, but it really helped."

Between trips they built buffer zones into the end of each day, going out for a quiet dinner "to hash over work-related stuff, so that by the time we got home, we were ready to drop it and just be us," says Stella. Now their 15-year-old son helps to keep them in line too. "If we start talking about the business when we're at home, he'll say, 'Hey, let's get off that subject, please.' And we do."

Above all, even if the sky is falling at the office, couples who have been there say they try, as the cliche goes, to never go to bed mad. Says Susanne Conrad, who with her husband, Brett, started a tech company called TwoJet: "We created a rule about not bringing crabby energy to bed. And we make love a lot. That always helps."

But let's suppose that, de-spite your best efforts, working with--or for--a spouse just drives you crazy. There's no disgrace in bailing, maybe even to start an enterprise of your own. "You can have a fantastic relationship, with complementary strengths and weaknesses, and still find that you do business very differently, so that you're better off separating your work lives," notes David Avalos. After a stint in TV production and market research at the E! entertainment network, he joined a production company in Burbank, Calif., called Media-Savvy that his wife, Adora English, had started with a partner a few years before. "We just have very different styles," he says now. "For instance, we'd meet with a client and I'd want to get right down to business, while Adora--and usually the client too--wanted to spend 20 minutes chit-chatting first about vacations, industry gossip, and whatever. I kept having to bite my tongue. It was frustrating."

About a year ago Avalos started his own novelty company, Insecurity Blanket. Of course, running two companies in one family takes a special kind of adaptability, especially since the couple just had their second baby in January. (What were they thinking?!) "It can be tough when she's working late into the night, and I have to be out of town at a trade show," says Avalos. "We take it one day at a time--'Okay, who needs what today?' So far, it's working."

Some dual-entrepreneur couples go to great lengths to synchronize their schedules. Take Tom and Renee Wall Rongen, who started two ventures in Erskine, Minn.--hers a consulting and speaking practice, his a crop-protection company--while adopting three newborns on three separate occasions. "We had some serious issues about whose job would come first and whose business growth would have to wait in the wings. We fought a lot," recalls Renee. "But after a lot of tears, anger, and frustration, we reached an agreement." She now schedules all her speaking and consulting engagements between September and March so she can be at home full-time during the spring and summer, Tom's busiest season. He takes over the home front in the cold months. As Tom explains, "To make this work, you've got to be very organized and disciplined. And surround yourself with good, reliable people, who can be hard to find. And don't lose faith."

It helps, too, to stay focused on what really matters. "My business could be ten times bigger if I were willing to work all year round and scale back on family time," muses Renee. "But both of Tom's parents died of cancer in their 50s, and we spent years taking care of them and then burying them. It puts a different perspective on things. Life is precious, and short."

True. It can also, if you are not careful, be mighty lonely. Anthony DeHart, the aforementioned machine-tool maven, came to that realization when his wife nearly left him. His own father, who had worked so long and hard for his entrepreneur grandfather that DeHart's mother divorced him, "is very well off materially but he's basically miserable. He lost his marriage." To spare himself the same fate, DeHart now makes it a point to get home by six almost every night, when he and Dottie cook dinner together and hang out with the kids. "I'm learning to say no to employees or customers who want to cut in on that time," he says. "I'm finding that most often people are okay with that. They respect it."

And if they don't, do you really care? You're the boss, aren't you?

John Drake is a psychologist who knows firsthand the pressures and perils of starting a business: He co-founded outplacement giant Drake Beam Morin. A few years ago he dropped everything and moved from New York City to Maine to spend time with his wife and now grown kids, whom he says he had neglected as a workaholic road warrior. He also wrote a book called Downshifting: How to Work Less and Enjoy Life More (Berrett-Koehler, $15.95).

Drake sees a strong marriage and happy home as a practical necessity--a kind of insurance policy against the slings and arrows of business life. "Sure, you can put your marriage on hold and pour all your energy into your company, and get all your self-esteem from that," he says. "But remember that the small-business failure rate is high, especially in this rotten economy. Is it really smart to put all your eggs in one basket?"

Anne Fisher writes the Ask Annie column for Fortune and is the author of If My Career's on the Fast Track, Where Do I Get a Road Map?