Now married with three children, Kalsoom Bibi and her husband Yousuf Bhatti have been shunned by their communities, endured death threats and an abduction, all in the name of religious honour in this conservative Islamic country.
Marriage out of choice remains a taboo in Pakistan, particularly when it involves a partner outside one's own clan or faith group.
While marriages between different members of Abrahamic faiths -- including Judaism, Christianity and Islam -- is permitted by law, a Muslim woman may not marry a non-Muslim man.
Kalsoom's first encounter with a member of another religion came at school, where the only Christian student was mercilessly bullied.
When she met Yousuf, she decided to question him about his faith to find out more. Long hours of discussion brought the two close together, and she eventually decided to convert.
It is a fact she hides to this day from her family.
"My mother died requesting me to leave my Christian husband," Kalsoom, a short woman in her twenties with deep brown eyes said, sitting on her bed in a modest two-room house with her husband and children.
Such unions aren't officially recorded but rights activists believe there are thousands of such cases every year.
The couple say they now live among a more understanding community that provides them support and respect their choices -- but it wasn't always this way.
"The life after marriage was terrible. We went into hiding because the family and community threatened to kill us.
"We lived in hiding in Islamabad for several months and my son was born during that time," she said.
"They kept me there for several days and asked me why I married my wife.
"They wanted to kill me, but when I told them that I married my wife with her own will and because she also wanted to marry me -- and that I did not force her into this marriage -- they softened and released me after some days," he added.
