A couple from my parish, I am not sure if they are actually married, have just been sent to prison, he is imprisoned locally, she is miles away. They are going to be separated for two years at least; no conjugal rights. In fact they will not even see one another. However if the were a homosexual couple they would be "banged up" (sorry) together and presumably be able to bring a certain pressure on the Home Office to serve their entire sentence together, doing whatever they wished to do in the privacy of their cell.
When marriage "equality" is introduced this is one of the anomalies that will have to be sorted out, why should a homosexual couple be more equal than a heterosexual couple when staying at Her Majesties pleasure?
Then of course in the future there will couples who meet and fall in love in prison and want to marry - now combine that with the European law that gives the right "family life".
Super Trad Mum has a similar story about about a heterosexual couple being separated in the Olympic village, whilst homosexual couples are not.