Envy is good for the economy. A survey by Virgin has found that British women spend £3.5 billion a year to copy the looks of the stars, with nine out of ten women polled admitting that they followed celebrity styles. Wanting to be like someone else might be invaluable for business, but what about when it’s closer to home? The recent film Envy, with Jack Black and Ben Stiller, saw envy blossom as one of the two pals made a fortune from an invention. The success of one was less the cement of their friendship than a corrosive force. As Gore Vidal famously put it: “Whenever a friend succeeds, a little something in me dies.”

If we can envy our friends, what about our lovers? This is where things get tricky. All relationships will at times involve a dose of hostility or jealousy. But jealousy is different from envy. You can be jealous of your partner’s relationship with someone else but envious of their self-sufficiency.

Envy is about someone else’s enjoyment of something that you are deprived of. It could be a house or a car, but equally their independence or youth. It’s the pot of honey to which you have no access.

In a relationship, your partner’s successes should be felt as something positive. If you identify with them, their achievement is also yours. If envy gets in the way, it shows that this identification is blocked. Their successes are felt to be excluding and depriving you. This can intensify to an unbearable point. If love is blind, envy is sharp-sighted. It scrutinises the smallest details only to magnify them. The other person has everything; you have nothing.

The irony is that envy is so often based on pure fantasy. The enjoyment we ascribe to the other person has no existence beyond our own thoughts. We hate them for our own projections. So why do we do it? Envy has its origins in childhood. We imagine that our parents enjoy something to which we have no access. They sleep together, eat together and have powers that no infant has. These banal facts of infancy can take on terrible proportions when a child feels frustrated. The feeling of being excluded nourishes the fantasy that the parent has what we lack.

Psychologists have argued that love is based on envy. We are attracted to someone who seems to possess the qualities we lack: power, wit, looks, money and so on. But this can explain obsession and infatuation rather than love. Love, on the contrary, is when we realise that the other person is not perfect, that they are human just like us.

The only remedy for envy is to give up the idea that someone else has everything. Once we realise that this is a fantasy, we can appreciate those we love and recognise that they are lacking, just like us.

Darian Leader is a psychoanalyst and author