If you left your spouse but your spouse did not want to leave, you cannot get a absolute divorce based on voluntary separation. Adultery Generally, when your spouse has had voluntary sexual relations with a person other than you, the lawful spouse, this is a basis for an absolute divorce. In this case you have to prove that your spouse committed the act of adultery. In order to prove adultery you have to prove disposition and opportunity. Disposition is when your spouse and someone else acted in a way that would lead you to believe that they committed the act of sexual intercourse.
Opportunity is the time they had to commit the act.
If you can prove these two elements, you can check off Adultery as a ground. In order to have actual desertion, you spouse must have left you, with the intention of ending the marriage. Constructive Desertion generally, Constructive Desertion occurs when your spouse has made your home conditions impossible for you and your children to continue to live together in safety, with health and self-respect. If there is an intent to desert, then the court will presume actual desertion. Insanity generally , permanent and incurable insanity is a ground for divorce.