According to this:

http://nlsa.us/resources/family/fam1_divorce.html

Marital misconduct, i.e. her sleeping around, has an effect on alimony in PA. In addition, there are three different kinds of divorce filing in PA. One is the old fashioned Fault divorce, one requires a two year separation, and the third is Mutual Consent.

In other words, PA is complicated. This should be enough to encourage the OP to get an attorney today.

You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.

You cannot over estimate the unimportance of nearly everything. John Maxwell