Illinois Marriage Dissolution Act

Sec. 401. Dissolution of marriage.
    (a) The court shall enter a judgment of dissolution of marriage if at the time the action was commenced one of the spouses was a resident of this State or was stationed in this State while a member of the armed services, and the residence or military presence had been maintained for 90 days next preceding the commencement of the action or the making of the finding; provided, however, that a finding of residence of a party in any judgment entered under this Act from January 1, 1982 through June 30, 1982 shall satisfy the former domicile requirements of this Act; and if one of the following grounds for dissolution has been proved: 

That, without cause or provocation by the petitioner: the respondent was at the time of such marriage, and continues to be naturally impotent; the respondent had a wife or husband living at the time of the marriage; the respondent had committed adultery subsequent to the marriage; the respondent has wilfully deserted or absented himself or herself from the petitioner for the space of one year, including any period during which litigation may have pended between the spouses for dissolution of marriage or legal separation; the respondent has been guilty of habitual drunkenness for the space of 2 years; the respondent has been guilty of gross and confirmed habits caused by the excessive use of addictive drugs for the space of 2 years, or has attempted the life of the other by poison or other means showing malice, or has been guilty of extreme and repeated physical or mental cruelty, or has been convicted of a felony or other infamous crime; or the respondent has infected the other with a sexually transmitted disease. "Excessive use of addictive drugs", as used in this Section, refers to use of an addictive drug by a person when using the drug becomes a controlling or a dominant purpose of his life