Annulment: A Declaration of Invalidity of Marriage Petition seeks a judicial ruling that a valid marriage never took place, that the marriage is not legally valid and that the marriage does not legally exist.

Legal Separation: A Legal Separation Petition seeks a judicial ruling that one spouse should pay another spouse child support or spousal maintenance, and distribution of property, without seeking to dissolve the marriage.

Divorce: A Dissolution of Marriage Petition seeks a judicial ruling that severs or dissolves a valid marriage.

The grounds for an Annulment include the following:

Generally, one who continues to cohabitate, one who ratifies, and one who fails to bring a claim for annulment within 90 days may not assert a claim for mental incapacity, fraud, physical incapacity, or duress.

For Legal Separation, one need not establish grounds. One need only establish that the parties are in fact living apart through no fault of the party who is filing for Legal Separation.

Fault grounds for divorce in Illinois include impotency, bigamy, adultery, desertion for one year, habitual drunkenness or drug addiction for two years, an attempt to take the life of the other, physical or mental cruelty, conviction of a felony or other infamous crime, infecting the other with a sexually transmitted disease.

No fault divorce is available if the parties have lived separate and apart for two years, or for six months by agreement, and irreconcilable differences cause the irretrievable breakdown of the marriage.