Who was the Greek woman that married Jason and killed her children as revenge?

The Greek woman you are referring to is Medea. In the myth, she marries Jason, who later abandons her for another woman. In a fit of rage and betrayal, Medea exacts her revenge by killing their children, an act that underscores her tragic and vengeful character in the stories surrounding her. This tale is famously depicted in Euripides' tragedy "Medea."