Pennsylvania is unusual among states in that it still has both no-fault and fault divorce options on the books. The many issues regarding divorce in PA are defined in Pennsylvania Statutes Title 23 Pa.C.S.A. Domestic Relations, Part IV.
Many states require some waiting period between when a divorce complaint is filed and when a divorce will be granted. In Pennsylvania, a no-fault divorce may be granted after a waiting period of 90 days provided both parties consent to the divorce at the conclusion of the waiting period. This waiting period is often referred to as a cooling-off period. It is arguably utilized in many states to give the parties an opportunity to reflect on the severity of the decision to get a divorce and/or seek marital counseling to see if the relationship can be saved. At this point, almost half of the states have some waiting period between when you file and when you can be divorced.
The divorce rate reached an all time high in the 1970's due to the introduction of no-fault divorce. A no-fault divorce meant that the parties could get a divorce without having to prove any wrong-doing in court. Essentially, all the parties have to do for a no-fault divorce is indicate the marriage is over. Prior to the influx of no-fault divorce, parties had to prove that the requirements for a fault divorce were met. Fault grounds for divorce in Pennsylvania include desertion, adultery, cruel and barbarous treatment, bigamy, imprisonment, and indignities. The majority of divorces will go through on the basis of no-fault since it is easier to litigate and often times there is no benefit in the outcome of the divorce to pursuing a fault ground for a divorce.