Jealousy is a major element. In a love triangle, when one person sees the object of their affection showing interest in someone else, it can trigger intense jealousy. Another element is betrayal. For example, if a person in a committed relationship starts seeing someone else secretly, that's a form of betrayal. And of course, passion. The strong emotions of love and desire that are misdirected or unfulfilled can lead to dangerous situations.
It's hard to say. There might be elements of truth in it, but it could also be largely fictional. You'd need to look into the background and origin of the story to know for sure.