Dear lybrate-user. Thanks for the question. Pathological jealousy, also known as Morbid jealousy, 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. Treatment success was notable for patients with dopamine
agonist induced Othello's syndrome in which all six patients had improvement in symptoms following decrease in medication. Wikipedia has a decent entry on morbid jealousy. Take care.