Forming a Professional Corporation is the only means by which a professional can obtain any meaningful level of liability protection, while maintaining control over employees of the organization. Employees do not need to be shareholders -- they must, however, be licensed, if they are shareholders, or if they are providing massage therapy to customers/clients.
If you have concerns about the organization, because you may want to have some level of management and control over the organization because you are the spouse of the licensed professional, your spouse can hire you as an employee for purposes of financial management, but you cannot control the employee's as to the manner and method by which they conduct their labor (unless you have a massage therapist license), and, you cannot own shares in the corporation. Your right to 50% ownership
of the equity value of business, is, however, confirmed by California community property case law. In the event of a divorce or your spouse's death, you would be entitled to 50% of the business value, or 100% if your spouse leaves you her half of the business as inheritance. You would have to sell the business as quickly as possible in the event of your spouse's death, because without a license, you cannot operate a massage therapy business, despite your right to the cash value of the business.
Hope this helps.