Will I have to share my business with my spouse after the divorce?

Even if you started your business and have contributed all work to the business, it is likely a marital/joint asset to be addressed in the divorce if it was started during the marriage.  Business interests are treated like all other assets in divorce: document and confirm the existence of the business assets, value the business itself and determine the marital/joint value or any separate/non-marital portion of it, and then negotiate the sale, co-ownership or buy-out of the business as part of the divorce settlement.