In any proceeding for divorce or judicial separation or restitution of conjugal rights, the respondent may not only oppose the relief sought on the ground of petitioner’s adultery, cruelty or desertion, but also make a counter-claim for any relief under this Act on that ground; and if the petitioner’s adultery, cruelty or desertion is proved, the court may give to the respondent any relief under this Act to which he or she would have been entitled if he or she had presented a petition seeking such relief on that ground.]