He followed her, checked the mileage on the car, listened in on her telephone conversations, quizzed her about her outings, opened her mail, insisted on meeting her from work and finally refused to believe that she was and always had been faithful to him.
The final straw came after he had spent several hours of a rainy night sitting in the bushes outside his own home, believing his wife was inside with her lover, only to discover that her mother had made a surprise visit. It was only then that he fully appreciated what was happening to him and sought treatment for his pathological jealousy.
According to Freud, jealousy in its milder forms is universal and inevitable. Its roots, he suggested, are in our childhood traumas and the inevitable Oedipal conflict, and if we don't experience jealousy when a relationship is under threat, then there is actually something wrong with us.
But it is when jealousy turns into pathological jealousy, or the Othello syndrome as it is now called, that problems begin to surface and treatment becomes necessary.
Increasing numbers of people are seeking medical and psychological help for their jealousy, and contributing factors are thought to include the rate of marital breakdowns and the rising number of working women, some of whose men are unable of coping with "losing" their partner.
New research also suggests that more people may also be seeking treatment because today there is less tolerance of jealousy, which has more and more come to be identified with lack of trust and stalking than with any real notion of romance or love.
As an emotion, jealousy is thought to originate during Freud's Oedipal state at the age of two to three years old. According to the founder of psychoanalysis, it is during this stage that we experience our first stirrings of sexuality, and these urges are directed at the closest person of the opposite sex, mum or dad.
But, the theory continues, the young toddler inevitably loses out and when in later life there is a threat to another relationship, the painful wound is reopened and experienced as jealousy.
For the majority of people, jealousy is a normal, healthy reaction that can actually improve relationships. For many others, it is an obsessive, irrational and often unfounded fear, where depression and anger can be triggered by an innocuous event such as a telephone caller who hangs up when they answer the phone.
"Jealousy is a response to a perceived threat to a valued relationship," says Dr Ayala Pines, author of A Romantic Jealousy, causes, symptoms and cures, which is published this week. "Although jealousy occurs in different forms and in varying degrees of intensity, it always results from an interaction between a certain predisposition and a particular triggering event.''
Predispositions to jealousy vary widely between individuals. For someone with a high predisposition, a triggering event can be as minor as a partner's glance at an attractive stranger passing by. For most people, however, the trigger for intense jealousy is a much more serious event, such as the discovery of an illicit affair. For others, the trigger can be imagined.
Dr Pines points out that there have been cultural changes in perceptions of jealously: "Until the 1960s, the message was that a certain amount of jealousy was natural, a proof of love and good for the marriage. Women were told to avoid situations that might make their husband jealous, but to interpret his expressions of jealousy as evidence of love.
"But around 1970, a new view of jealousy started to take root. This emerging view was that jealousy was not natural. Jealousy was no longer seen as a proof of love, but evidence of a defect such as low self-esteem or the inability to trust.''
It's when jealousy gets out of hand that treatment is needed quickly. It is one of the most powerful emotions and can lead to violence, murder and suicide. It can also damage physical and mental health, and ruin relationships.
"Jealousy can quickly become problematical and pathological," according to Professor Petruska Clarkson, a psychologist who deals with cases of jealousy at her London practice. "It is based on insecurity and a low self-esteem. Then it can take the form of wanting to possess the partner, restricting their liberty or controlling their behaviour which rapidly becomes self-defeating.
"The most common cure is to value yourself more and to learn to find love, and also to value people who freely love you and prefer to be with you. When jealousy has become pathological, professional counselling should be sought because it can become as crippling and disabling as a life-threatening disease at the emotional level and interfere with all aspects of life.''
Stressful life events such as job loss, death of a parent and ill health, can act as triggering events for pathological jealousy and some people, such as those whose self-esteem is low or who have a generally more suspicious nature, may be more easily triggered.
Individual reactions to jealousy vary enormously. In her research, Dr Pines found that 7 per cent of partners, both men and women, resorted to violence, and 30 per cent said they left the relationship. Forty two per cent sulk and a third retaliate with copycat behaviour, but 55 per cent said that they fully accepted the situation.
According to the American Psychiatric Association, people with paranoid personality disorders may experience pathological jealousy: "They often suspect that their spouse or partner is unfaithful without any adequate justification. They may gather trivial and circumstantial evidence to support their beliefs. They may want to maintain complete control of intimate relationships to avoid being betrayed.''
There is a range of different therapies for treating unwanted or uncontrollable jealousy, including couple counselling, hypnosis, behaviour dampening drugs, antidepressants, behaviour therapy and psychoanalysis.
When a patient's jealousy has been triggered by an identifiable event, such as a partner talking to another man/woman at a party or a partner going to work for the first time, that can be tackled with a programme of desensitisation to these cues using behavioural therapy techniques.
In this exposure and response approach, the patient is exposed to cues which provoke these jealousy-related behaviours, and then agrees that for a period of time they will refrain from that behaviour. Anger control therapy is also used for those who suffer pathological jealousy, as well as assertion training for their partners.
In implosion therapy, the patient is taught to imagine his of her worst fear again and again so that the real fear reduces. In Dutch Cow Therapy - so called because the telephone takes the place of the bells worn by cows to let their owner know where they are - the guilty but contrite partner agrees to ring home every hour. In Pretend Therapy, the non-jealous partner is helped to look at the world through the eyes of the wife/husband.
If the therapy or drug treatment is successful, jealousy should be containable. In some cases it may well disappear altogether, and in a very small number of instances it just might turn into pathological tolerance.
This rare condition, which is also known as psychological scotoma, is where the sufferer has a total inability to recognise jealousy triggers that are completely obvious to everyone else. Now, if only Desdemona could have married someone like that....
`A Romantic Jealousy, causes, symptoms and cures', by Ayala Malach Pines is published by Routledge on Friday, pounds 12.99
Just a Jealous
Top 10 reasons for jealousy
1. Personal insecurity
2. Fear of losing face
3. Fear of being excluded
4. Threat to privacy of intimate relationship
6. Feelings of inadequacy
7. Fear of losing control
8. Fear of loss
How much jealously based on a scale of one to seven would you experience if
1. Announced they had fallen in love and was thinking of leaving you
2. Had a serious long term affair
3. Had an affair but was open about it and said it was caused by a need for variety and would not affect your relationship
4. Recently had a one night stand
5. Had a relationship many years ago before you met
6. Had an affair many years ago after you had met
7. Had an affair many years ago after you had met and with someone who is now dead
8. Had a relationship many years ago before you met with someone who is now dead
0 to 16: Unbelievably trusting
16 to 28: Mildly jealous
29 to 36: Moderately jealous
37 to 53: Green-eyed monster is looming
44 to 48: See a doctorReuse content