Lucille Ball and Desi Arnaz made a great team both as comics and as business partners. Their Desilu empire became a Hollywood powerhouse. But they weren't such a great team as spouses. They divorced, and Ball bought out her former husband.

Other couples aren't so lucky. Often, business-owning spouses pitch in on everything, without considering what would happen if the company thrived but the marriage failed. When divorce approaches, they may fight over who contributed most to the company, sometimes dragging employees into the battle. And if neither spouse can afford to buy out the other, sometimes the business must be sold.

What's an unhappily married entrepreneur to do? First, if you have a prenup, make sure to abide by its terms; otherwise, it could be declared invalid. If you don't have a prenup, develop an ownership agreement, so your spouse can't sell shares to anyone but you. Keep detailed records on everything you do for the company, in case there's a dispute over ownership. And establish an agreement on how the business would be valued in case of divorce. Your company's future may depend on it.