Wednesday 31 August, 2005 (REUTERS)

It may have been one of the first countries to legalise gay marriage, but now Canada has accepted a less celebratory legal change. In the first case of its kind, one of the country’s Supreme Courts has ruled that a married man who had an affair with a gay man did commit adultery.

Previously, his wife had not been formally granted a divorce, because extra-marital relations with a person of the same-sex was not counted as adultery. However, with the country recently announcing it would legalise gay marriage, judges conceded that the change was necessary.

And although the change is aimed at a heterosexual couple in this instance, any lesbian or gay couples who look to divorce in the future because of affairs will be able to.

The ruling was made yesterday by the British Columbia Supreme Court by Justice Nicole Garson, who ruled in February that Ms P, as the wife can only be referred to, could not have an immediate divorce.

Under Canadian law, only adultery or cruelty can be seen as a reason for immediate divorce. Other reasons mean married couples must separate for at least a year before filing for formal divorce.

"We argued that the historic definition of adultery, which is limited to sex between a spouse and someone of the opposite gender, was anachronistic in light of changes to the Marriage Act and changes to the understanding of same sex marriage and divorce," Ms P’s lawyer, Barbara Findlay said.

Canada was the fourth country to legalise gay marriage, after the Netherlands, Belgium and Spain. The US state of Massachusetts also allows gay marriage.

Previously provinces across the country ruled that barring lesbian and gay couples from marriage was discriminatory.

Elsewhere, including the UK, civil union packages are offered to lesbian and gay people.