Ernestine Kabuo returned home after fleeing the lava flow in Goma, Democratic Republic of Congo, to find that her husband had not survived.
The 68-year-old was unable to carry her sick husband out of their house and she found him burnt to death, she told Reuters news agency.
At least 22 deaths have been confirmed following Saturday’s eruption of a nearby volcano, Mount Nyiragongo.
But the lava stopped short of the city’s built-up area.
This avoided the level of death and destruction witnessed in 2002. It did, however, hit the Buhene district, where Ms Kabuo’s home was.
“I said to myself: I can’t go alone, we’ve been married for the best and for the worst,” she told Reuters reflecting on what happened on Saturday.
“I went back to at least try to get him out but couldn’t. I ran away and he got burned inside. I don’t know what to do. I curse this day.”
Five people died of asphyxiation while trying to cross the lava when it was cooling in a place just north of Goma.
A sixth person is in hospital with breathing difficulties, civil society leader Mambo Kawaya told the AFP news agency.
Since then, the authorities have tried to prevent people from visiting places where the lava is cooling, Goma journalist Esdras Tsongo told the BBC’s Focus on Africa radio programme.
Other Goma residents, a city of 670,000 according to UN estimates, are searching for missing loved ones as the city, and the region, continue to experience earthquakes.
More than 170 children are feared to be missing and 150 others had been separated from their families, the UN’s children’s agency, Unicef, said, adding that centres would be set up to help unaccompanied minors.