Officers were called to the parking lot outside a Dollar General in the 900 block of north McDonald Road about 9:30 a.m. Tuesday.
The victim, Mishell Jones, 49, was taken to Medical Center of McKinney in critical condition and later died from her injuries.
Police detained James Otis Jones, 44, at the scene of the crime for questioning and later arrested and charged him for Mishell's murder.
Mishell's oldest daughter, Natia Burns, says Mishell lived life with kindness, and that may have ultimately led to her death after opening her home again to James, her ex, after he was released from jail last April.
"No matter what the outside world may think, my mom was caring, very loving and willing to help anybody, even him," said Burns.
According to a probable cause affidavit for the case, James said he thought about killing the victim for four to five months. He admitted that they argued a lot because he was using their rent and food money to buy and smoke crack.
"They've argued before, but never to where I thought he would kill her," said Burns.
Court documents say Mishell told James to move out by Thursday, and that's when he decided he was going to kill her and hid two knives under the seat in their car.
McKinney police say just before they were called to the scene Tuesday morning, the couple had stopped at the Dollar General to buy bread.
Police say they started arguing, and after returning to their 2004 Pontiac, James took out a knife and started stabbing Mishell in the neck and chest.
When she grabbed it, police say James took out a second knife and stabbed her more.
"To lose somebody as good as my mom, it brings tears to my eyes," said Burns.
James has a history of convictions, including burglary, theft, violations of protective orders and an aggravated kidnapping charge that he served 10 years in prison for.
James was at one time a suspect in the 2004 McKinney quadruple murders and even confessed.
Four people were shot execution-style during a botched robbery at a home of Rosa Barbosa on Truett Street.
Rosa, her nephew Mark and his two friends, high school football players Matthew Self and Austin York, were killed.
James had been a police informant, but his attorney said James was on crack when he confessed.
The murder charges were dropped and two other men were convicted.