Quiet Kill.

An attractive married woman and a member of the 'Country Club Tennis Set', is being neglected by her workaholic doctor husband, Jerry (Corbin Bernsen). Lonely and insecure, Amy foolishly falls for the seductive charms of a much younger man, Steve Sterns (Nicholas Celozzi) who is introduced to Amy by her good friend, Sheila. The love affair is very brief, as she realizes that Steve has a dark, sinister and obsessive side to his personality, or is it personalities? Amy tries to break off the relationship, only to find that her adulterous lover has become her stalker. She also fears that Steve is responsible for the numerous brutal murders of local prostitutes.