Brendan Cox says his wife was worried about the "coarsening" of politics.
Jo Cox, a Labour lawmaker who had championed the cause of Syrian refugees, was stabbed and shot to death outside a library in her constituency on Thursday.
The suspect gave his name in court as "death to traitors, freedom for Britain."
Her death brought a shocked pause in campaigning for Britain's EU referendum.
In a televised interview today, Brendan Cox said his wife "was very worried that the language was coarsening, that people were being driven to take more extreme positions."