Alimony Laws in IL determine spousal support based on marriage length, income disparity, and ability to be self-sufficient. Learn about the types of alimony available in Illinois, how it's calculated, and the factors courts consider when awarding spousal maintenance.In fact, Illinois law states that determinations regarding spousal maintenance will be made "without regard to marital misconduct. Use the alimony calculator below to estimate your spousal maintenance in Illinois. Download and complete Divorce, Child Support, and Maintenance forms from the Illinois Office of the Courts. In Illinois there are five main types of alimony or spousal support; temporary, fixedterm, reviewable, permanent, and lumpsum. How a new spouse's income can affect alimony after an Illinois divorce. This alimony calculator is intended only to give a general idea of your spousal maintenance calculations. Maintenance, sometimes referred to as alimony or spousal support, is financial support that one spouse pays to the other in the event of a divorce. Alimony is a courtordered provision for a spouse after a divorce.