A spouse in this classification is employment-authorized incident to status and may take outside employment. The principal investor is expected to develop and direct the enterprise, so their own time should be devoted to it.
One inside the business, one outside, is a normal pattern
Couples opening a first unit often need income while the business finds its footing, and the classification accommodates that on the dependent side. The spouse's authorization to work arises from the status itself, so employment with an unrelated employer is available, subject to satisfying an employer's ordinary verification requirements. The principal is in a different position.
Because the requirement is to develop and direct the enterprise, a principal who takes a full-time job elsewhere invites the question of who is actually running the business. Where both members of a couple are named as investors, both are expected to be involved, and the application should describe how responsibilities are divided rather than leaving the impression that one name is decorative.