Section 186 - Evidence by spouse as to adultery.

The parties to any proceeding instituted in consequence of adultery and the husbands and wives of the parties shall be competent to give evidence in the proceeding, but no witness in any such proceeding whether a party to them or not, shall be liable to be asked or bound to answer any question tending to show that he or she has been guilty of adultery, unless he or she has already given evidence in the same proceeding in disproof of the alleged adultery.