In Brooke and Brad Antonioni's old office, they sat back to back at their respective corner desks.

Being so close for the whole day didn't bother the couple, who have been married for 14 years. It was just like any other working relationship, they said.

"We would find ourselves in the same room having email conversations back and forth," said Brooke Antonioni, 35. "We would have to stop ourselves and say, 'We're in the same room, let's just talk about this.'"

The Antonionis, who run security and maintenance services company Trans-West, are a Bakersfield example of a little-noticed trend that finds more than a million American married couples running a business together.

Married couples who go into business together say they face some additional obstacles compared to most business owners. Namely, they must find a way to keep their home life and their office life separate. But those couples say as long as they establish firm guidelines, the business and the marriage should both stay afloat.

In 2002, 3.9 million businesses in America were family owned, according to the U.S. Census Bureau's Survey of Business Owners from that year. In the survey, a family-owned business is defined as one that is jointly owned by spouses, parents, brothers, sisters or close relatives.

In 2007, the last year the survey was administered, the Survey of Business Owners isolated how many businesses were jointly owned by spouses. In that year, 1.4 million were jointly owned and equally operated by spouses.

Bruce Busacca, 50, started security company Secure Systems in 1980. In 1988, he married his wife, Molly, 47. Two years later, she quit her job and went to work at Secure full time. Now, they're co-owners.

"At the time it was really scary to leave my job," Molly Busacca said. "But looking back on it, it went really smoothly."

Molly Busacca's trepidation over getting into business with her husband was assuaged as she started going on sales calls and met other couples who worked together. Their No. 1 piece of advice, she recalled: "Only one of you can be the boss."

Bruce Busacca attributed their continuing success in business and marriage to the fact that they set goals and try to separate their jobs as much as possible. For example, Molly Busacca takes care of most of the work in their office on 24th Street, while Bruce Busacca does most of the field work.

The Busaccas also write down personal goals, family goals and business goals like when they are going to retire, what they want their triplets to do and what the business should purchase.

"If we have a disagreement, it's usually about an idea, not a goal," Bruce Busacca said.

For example, shortly after Molly Busacca joined the company, she suggested changing the name from Secure to Secure Systems. The idea was not right for the time, they eventually agreed. But seven years later, Molly Busacca ultimately got her way when the name was officially changed to Secure Systems to reflect the business' expansion.

Ira and Mary Sullivan also said they believe the key to successfully owning a business with a spouse is doing somewhat separate jobs. The Sullivans have owned Kern Trophies for 11 years. They've been married for 12.

Ira Sullivan, 74, mostly handles building the trophies and plaques, while Mary Sullivan is more involved in creating the graphics and layout.

Mary Sullivan, 59, started working at Kern Trophies in 1997. When the couple bought the store from the former owner in 2001, there wasn't a discussion about what that might do to their 1-year-old marriage. They had both come from previous marriages -- Mary Sullivan was widowed and Ira Sullivan divorced -- where they also worked with their spouses.

"If he acts up, I just send him home," Mary Sullivan said with a laugh.

And they don't actively try to keep work out of the home. In fact, it's the opposite. It's easier and more relaxing to finish big orders at home, they said. More important, they said, is not bringing fights from home into the office so their employees don't feel uncomfortable.

The Sullivans said working together while married is fine, as long as each person follows the three Cs: communication, consideration and cooperation.

"And I added a fourth one," Mary Sullivan joked. "Credit card."

Brooke and Brad Antonioni, who run Trans-West, have been inseparable for most of their relationship. They both got their master's in business and public administration from Cal State Bakersfield. There, they took every single class together.

Running the business together helps their marriage, they said, because it means neither one feels out of the loop. For example, they both go on business trips to places like San Luis Obispo and Santa Maria. So neither of them feels the other is getting to travel more, they said.

But they set ground rules for keeping business and marriage separate. For instance, date nights have specific times when business talk is allowed.

"If we're on the appetizers we're allowed to talk business," Brad Antonioni said. "But after that, it stops."

As for their shared office, they said it made sense because their jobs are closely connected. Brooke Antonioni focuses on the security side of the business, while Brad Antonioni mostly takes care of the numbers. But they always bounce ideas off each other, they said.

They gave up that shared office to four employees who needed the space. Now, they're floating around the office conference rooms. But, they still mostly sit side by side.

"We love it," Brooke Antonioni said. "It's fun for us to be part of each other's day."