Surprisingly readable novel about Jane, a woman who takes a leave of absence from her job to exact revenge against the man who broke up with her best friend, which led to her suicide. She seduces this man and plots her revenge, but the part that kept me reading was Jane's internal monologues diagnosing her own sociopathy.
Absolutely fascinating. AND, the author is Victoria Dahl, who writes terrific romances that include older, non-traditional heroines. So fun!
Ooh, there's a sequel! Problem Child (2020).