Depending upon corporate structure and legal jurisdiction, certain funding streams (loans, lines of credit, guarantees) WILL require both the founder and their spouse to sign on the dotted line. This places the spouse on the financial hook as much as the founder, preventing the squirreling away of assets out of reach of creditors. It also makes the spouse a "silent" investor in the company.

I have only seen this a couple times. In both cases, the corporate structures were LLCs, and the amounts were over a million.