Adultery is the term used for voluntary sexual relations between an individual who is married and someone who is not the individual’s spouse. When a married person has sexual relations with someone who is not his or her spouse, he or she commits adultery.

The only ground for divorce in Hong Kong is that “the marriage has broken down irretrievably”. According to section 11 of the Matrimonial Causes Ordinance (MCO), adultery is one of the five “facts” a party can use to prove that the marriage has broken down irretrievably, and the petitioner has to establish the fact of adultery.

Under section 11A(a) of the MCO , to establish the fact of adultery, the petitioner must show two things:

1. the petitioner’s spouse has committed adultery, and
2. the petitioner finds it intolerable to live with the spouse who has committed adultery.

Point (2) above is a test from the  subjective point of view of the adulterer’s spouse as to whether or not he/she finds it intolerable to live with the adulterer. The feeling of intolerance does not have to be related to the adultery: it may be a result of the adultery, but it may also relate to some other behavior of the adulterer.

Time limit

If the parties continue to live together for more than six months following the act of adultery, the petitioner will not be entitled to rely on the fact of adultery because the petitioner will not be able to show that he/she finds it intolerable to live with his/her spouse who has committed adultery.

Proof

It is not a requirement that the person who committed adultery with the respondent is identified. The petition and confession statement could state that the respondent committed adultery with a person unknown to the petitioner, or the petitioner can choose to disclose the identity of the person if the petitioner knows who that person is.

The petitioner must have certain knowledge that adultery has occurred , not only a belief that there has been adultery. The standard of proof is? “a preponderance of probability” and there is also a presumption of innocence to overcome. Whoever raises the allegation of adultery has to prove it.