Grounds for divorce according to Pennsylvania law fall into two categories: "fault" and "no-fault" divorces.

In a "fault" divorce, one spouse alleges that the other spouse is at fault for the divorce. The "innocent" spouse must show that the "faulting" spouse engaged in some type of misconduct, which led to the divorce.

There are a number of fault grounds for divorce in Pennsylvania, including:

abandonment for a period of at least one year;
adultery;
cruel and barbarous treatment, such as physical or mental abuse, or other behavior which made married life intolerable;
bigamy;
institutionalization; and
imprisonment, in which a spouse was sentenced to a term of incarceration for two or more years.

In addition, a judge may consider poor behavior when deciding whether to award alimony. For example, if a spouse cheats and then requests alimony as part of a divorce, although rare, a judge may reduce or deny alimony because of the indiscretion.

It should be noted that since the adoption of no-fault divorces in Pennsylvania, the vast majority of divorces are finalized pursuant to the no-fault provisions of the Pennsylvania Divorce Code as establishment of a fault rarely results in a monetary advantage to the establishing party.

A "no-fault" divorce in Pennsylvania is based on one ground: the "irretrievable breakdown" of the marriage. For and expedient divorce, both parties must consent that the marriage is irretrievably broken and sign affidavits attesting to the same. Otherwise, the consenting spouse will be unable to proceed until two years have elapsed from the date of the parties' separation.