Yes. Wisconsin is a community property state which means that assets and debts acquired during the marriage, with the exception of property received by gift or inheritance, are divided equally.
If you start a business during the marriage, a court may consider the value of the business, including assets and receivables, as marital property. This means that your spouse may receive a part, or even half of your business in a divorce. Since it may be difficult to physically divide a business, a court may give your ex-spouse another marital asset that may be equal the value of the business. The court may also order assets from the business to be paid to the ex-spouse.