"I've relived it over and over and every time I close my eyes, I see my babies… I see them dead. Every time I close my eyes, you don't want to know what I see," she said.
Simpson said her ex-husband became angry with her on Tuesday in a phone after she rejected his pleas to rekindle their relationship.
According to CBS DFW, he walked into Simpson's home Wednesday morning in Ponder, a town of about 2,000 residents about 40 miles northwest of Dallas, and opened fire at Simpson, her boyfriend and her children.
CBS DFW says Simpson and Painter were married in 2012 in Tarrant County and filed for divorce in 2017, according to public records.
Authorities have not confirmed the ages of the children.