No divorce for adultery shall be granted on the uncorroborated testimony of a prostitute, or a particeps criminis, or when it appears that the parties voluntarily cohabited after the knowledge of the adultery, or that it occurred more than three years before the institution of the action; nor shall a divorce be granted for any cause when it appears that the offense charged has been condoned, or was committed by the procurement or connivance of the plaintiff, or that the plaintiff has, within three years before the institution of action, been guilty of adultery not condoned, but such exception shall not be applicable to causes of action brought pursuant to sections 5-201 and 5-202 of this chapter. The defense of collusion shall not be pleaded as a bar to a divorce.