Morbid jealousy

Morbid jealousy, also known as Othello syndrome or delusional jealousy, is a psychological disorder in which a person is preoccupied with the thought that their spouse or sexual partner is being unfaithful without having any real proof, along with socially unacceptable or abnormal behaviour related to these thoughts. The most common cited forms of psychopathology in morbid jealousy are delusions and obsessions. It is considered a subtype of delusional disorder.