Indian court rules that any couple who have sex are legally married... and would need to divorce if they want to sleep with someone else
Any couple who have sex to be considered married, Madras High Court rules
This means they would also need to divorce should they break up
Either of them could register the 'marriage' if they can prove they had sex
The legal registration could be done without the other persons approval
http://www.dailymail.co.uk/news/article-2344575/Indian-court-rules-couple-sex-legally-married--technically-need-divorce-wanted-sleep-else.html