Watched this series “Stalked: Someone’ …

Watched this series “Stalked: Someone’s Watching” on Netflix. At one point they cited a guy begging his wife not leave as a “red flag.”

I wondered when we went from “I know you wanna leave me,
But I refuse to let you go
If I have to beg and plead for your sympathy,
I don’t mind coz’ you mean that much to me”
being appropriate romantic lyrics to being a “red flag” of criminal behavior.