If I'm a stay-at-home dad and my wife started her own cleaning company, since she wants a divorce am I entitled to any alimony and a piece of the business?

Each spouse is entitled to live in something similar to the marital standard of living after dissolution and has an obligation to support their spouse.  So--a court would award temporary and then permanent support. 

The "piece of the business" is a trickier concept.  If you were not a partner and she ran the business herself--but it was developed during the marriage you would most likely have a community interest.  The most difficult and time-consuming aspect of determining the value of a business or professional practice is in evaluation of "goodwill." This is the intangible value that most businesses have, which is based on the expectation of future business, based on established name or reputation. If the business or practice is operated by one of the spouses, it has a goodwill value even if it could not be sold on the open market.

Often, a business person or professional will say, "How can there be any goodwill . . . if I stop working, the office does not make any money?" The law's answer is that the goodwill of a business or professional practice is valued as a "going concern." That is, the law assumes that the business will continue operating and will not lose any customers that would otherwise have been lost if it were sold to another owner.  Certified public accountant and business appraisers are hired to determine the value of a business or professional practice. The accountant or appraiser who is hired reviews the books and records of the business or practice and prepares a written report.

You should really consult with a family law/divorce attorney near you to ensure the best result.