(a) General rule.--Existing common-law defenses are retained as to the grounds enumerated in section 3301(a) and (b) (relating to grounds for divorce). The defenses of condonation, connivance, collusion, recrimination and provocation are abolished as to the grounds enumerated in section 3301(c) and (d).
(b) Adultery.--In an action for divorce on the ground of adultery, it is a good defense and a perpetual bar against the action if the defendant alleges and proves, or if it appears in the evidence, that the plaintiff:
(1) has been guilty of like conduct;
(2) has admitted the defendant into conjugal society or embraces after the plaintiff knew of the fact;
(3) allowed the defendant's prostitution or received hire from it; or
(4) exposed the defendant to lewd company whereby the defendant became involved in the adultery.