By Kylie Morris
BBC News, Bangkok
Aids has long been a problem in Cambodia, although married women have never been seen as a particular risk category.
Sina became HIV positive through her husband
But the latest figures paint an alarming picture - wives now account for 42% of all new HIV infections in Cambodia.
Across the country, monogamous married women must now consider whether their husbands are putting them at risk.
For Sina, the nightmare has become a reality. Her husband, Sophat, spent many nights away from home, but Sina says she was too scared to stop him.
She also says she had never heard about condoms until after the couple were infected. Now they are left only with anger and regret.
"At first I was really angry with my husband, because he's the one who made me ill," said Sina.
"I wanted to drown myself in the river, but I didn't because my children are still so young."
Julie Hoare, from the Australian Red Cross, said women like Sina were far from isolated cases.
"The greatest risk for women in South-East Asia is being married, because husbands are bringing the disease home to their wives," she said.
Sophat's three closest friends have already died of Aids, and so too have their wives.
Sina and Sophat are among the lucky 4% of Cambodian HIV/Aids sufferers who get the ant-retroviral drugs they need - in their case, from international agencies.
But for Sophat, there are already more bad days than good.
"I'm trying to look after myself the best I can, so that I can see my children grow. We've asked charities to care for them after we are gone. Beyond that I have no hope," he said.
Sophat and his friends were all policemen - a profession with a reputation for patronising brothels.
HIV has forced many police officers back to the classroom, where they are learning how to protect themselves, as well as the women they have sex with.
Cambodian police officers are a high-risk group
One in four sex workers across Cambodia is thought to be HIV positive, and their only protection is to use condoms.
"In the past customers didn't want to use condoms, but now they know better," said 19-year-old prostitute Linda.
But for some men, it remains a different story when they go home to their wives.
These days, trust is a virtue few couples can afford. The only certainty can be found in a blood test at an HIV clinic.