The factory co-owner, 46, was killed with a shot to his back in the rib cage, earlier thought to have been shot by a sniper, while repairing a gazebo at the couple's home in southern Russia, Moscow's RIA Novosti reported Sunday.
The couple fought continually throughout their seven-year marriage and had argued earlier that day, police said.
The man died at home in the Volgograd Region on June 9. His wife called for police and an ambulance, but he died before paramedics arrived at the scene, RIA Novosti reported.
The wife, whose name was not released, wrote her confession and was detained, said Investigative Committee spokeswoman Nataliya Kunitskaya.
The suspect has been charged with illegal acquisition of a weapon and murder, which carries a maximum sentence of 15 years in prison, RIA Novosti reported.