If you have a gay marriage it looks as though you might not be able to get divorced, because divorce laws aren't being changed to accommodate it.
Gay marriage: divorces over adultery face legal challenge - Telegraph
" Gay partners who have an affair with someone of the same sex will not be able to use adultery as grounds for divorce because the legal definition involves intercourse between a man and a woman.
Under the government’s plans, same-sex couples will also be unable to annul their marriages on the basis of non-consummation, for similar reasons.
However, heterosexual married couples will continue to be able to use adultery and non-consummation as grounds for divorce, a discrepancy which lawyers said amounted to “clear discrimination”.
The Government has suggested that creating an equivalent of adultery and non-consummation for same-sex relationships would change the law “unnecessarily”. "