adultery
the ground of adultery can be used where your spouse has had sexual intercourse with someone else of the opposite sex (so if your husband had sex with a man this does not count as adultery). it must be actual sexual intercourse - not just a kiss or ‘heavy petting’.
if you decide to file for divorce on grounds of adultery, you must do so within 6 months of discovering that your spouse cheated on you. but you cannot give adultery as a reason if you lived together as a couple for 6 months after you found out about it.
you can only use the ground of adultery if you are the ‘innocent’ party (ie your spouse slept with someone else, and not if you committed adultery). however, if you both had sexual relationships with other people, either spouse can file for divorce.
unreasonable behaviour
there are essentially two distinct situations where the ground of unreasonable behaviour is given in a divorce petition: first, where unreasonable behaviour has occurred, and second where none of the other grounds for divorce applies (eg where both spouses have simply drifted apart and no longer wish to remain married).
although unreasonable behaviour can constitute serious accusations including domestic violence or drunkenness, it also encompasses rather vague issues such as lack of support in maintaining a household. in reality, there is a very low standard when it comes to unreasonable behaviour, but some factual reason must be given and an incident of ‘unreasonable behaviour’ must have occurred less than 6 months before filing for divorce
it should be noted that, if your partner has become intimate with someone else but has not had sexual relations with them, although adultery cannot be given as a ground for divorce, unreasonable behaviour can be used. similarly, if your spouse has a sexual relationship with a member of the same sex, this does not count as adultery but can count as unreasonable behaviour.
living apart for one year (with agreement)
if you and your spouse have lived apart for at least one year, and you both agree to get divorced, this ground can be used.
even where you got back together for a period of up to 6 months within the one year, the one year of living apart will continue to count as continuous. however, the 6 month period cannot count towards the one year of living apart.
living apart for more than 2 years (without agreement)
if you have not been living with your spouse for at least 2 years, you can file for divorce on this ground, even if your spouse does not agree to divorce.
applying for an interim gender recognition certificate
a marriage can be ended on this ground by a transgender person who has an interim gender recognition certificate. to obtain such a certificate, they must apply to a gender recognition panel. for more information on this, please read the government's guidance on applying for a gender recognition certificate.
for more information about divorce, read the divorce process in scotland.