There are three grounds for divorce in Pennsylvania with the most common being "no fault":
One spouse must prove two things: (1) that he or she is an innocent and injured party; and (2) the other spouse is guilty of marital misconduct such as desertion, adultery, cruel and barbarous treatment, bigamy, imprisonment for a crime, or indignities.
A no fault divorce can be filed without establishing any guilt towards one of the spouses and the innocent or injured status of the other spouse. In a no-fault divorce, one party files a divorce complaint. If both parties agree, then, after 90 days, both parties may file documents indicating their consent and the divorce is granted.
If one spouse has a serious mental disorder or is insane and has been confined to a mental institution for at least 18 months with no reasonable prospect of discharge during the following 18 months, a divorce may be granted.