Mark Moat, 42, was arrested after Sandra Nowocinska, aged 22, died in hospital four days after being rescued from the fire.
Her five-year-old son, was also injured in the fire in the flat above a shop in Kidderminster on November 27.
Moat was yesterday charged with manslaughter and arson being reckless as to whether life of another would be endangered.
He was also charged with arson and threatening to cause criminal damage in relation to two separate incidents.
Moat appeared at Kidderminster Magistrates Court this afternoon, and will next appear at Worcester Crown Court on June 1.