The woman had suspected her boyfriend of going after another lady.
The victim, a 31-year-old mechanic, Alfred Amamoo Eshun escaped death but lost several of his properties in the fire.
Maame Efua Ahema, an elder sister of the victim told Skyy Power FM that the incident happened around 11:30 pm on Monday when her brother was fast asleep.
According to her, her brother and the suspect have been in a relationship for about ten years with three children.
However, there has been a misunderstanding between the two and they have since been living in different rented rooms in the same house at Appremdu, a suburb of Sekondi/Takoradi.
The suspect, however, on December 11, 2017, suspected her boyfriend of cheating on her with another lady in the neighbourhood.
She allegedly sneaked into the man’s room whilst he was asleep and set him ablaze.
The man escaped death but sustained severe burns and is currently receiving treatment at the Kwesimintsim Hospital.