Why does she do it? Why does any woman do it?
"I've met people in the counselling rooms who are attracted to people who are less than good for them, and these people perpetuate some of the difficulties they've had in the past," says Julia Cole, spokesperson of Relate. "Once a woman has encountered someone difficult the first time round she may feel that men like that may not be suitable, but at least they're familiar and she can deal with them, even though they're less than perfect. Sometimes I've met couples in which the women are in difficulties, even though their sex lives are fine and their men are kind and considerate - and yet it's hard for the woman because she's used to rotters who let her down. She doesn't know how to deal with someone who really cares for her and she finds such people dangerous. With someone you're really close to you let your barriers down to make way for intimacy, and while most people find this pleasant, an emotionally deprived woman may find it very frightening. She's used to the roller-coaster ride with someone who's wonderful one minute and lets them down the next, but they can't cope with someone normal."
Diana fits this pattern perfectly. And indeed what was so sad about her relationship with Charles was that she wasn't even able to spot that it was incomplete. They'd obviously never got really intimate and cosy. It was said she called him "Sir" up to the marriage, and certainly when asked if they were in love on television and Charles nodded his head and added, bizarrely, "whatever love is", alarms bells would have started going in the heads of most women. Not, interestingly, Diana's.
Her background (especially her relationship with her father) had not equipped her with alarm bells, or at least had not equipped her to respond to them properly. Her mother ran off with a wallpaper millionaire when she was only six, and left Diana feeling bereft. She used to cry bitterly in the bedroom with her brother, longing for her return. This was perhaps her first betrayal and the first moment Diana started to draw up any trusting drawbridge she might have had before. All she had left was her father, an emotionally unavailable man who became even less available after his stroke. He was a man who, after his illness, was "all here but not all there". He remarried a stepmother who Diana loathed at the time. Would that experience not be enough to make a woman behave providently in her own emotional life?
Precisely the opposite. She is trapped by her past: in many ways you could view Diana's present as being an endless re-enactment of it. She finds a man who's emotionally unavailable, and at least she feels at home. Like so many women, Diana looks for the devil she knows - and the devil she knows may well not be good for her.
"I would say she was a case of someone suffering from a case of emotional anorexia," says Corinne Sweet, author of a book on addiction, Off the Hook. "Given her eating disorders it's clear that she emotionally starves herself of what she needs. You could say she settles for crumbs rather than the food she should have. Or you could say that she simply misreads the signs - she's one of those women who go to the shoe shop to find bread. If she did have someone who loved her as a person and not just as a fantasy princess, she'd have to face in herself exactly what she can't bear to face - her deep feelings of rejection, anger and low self-esteem."
Most of the men in Diana's life have had other women lurking about somewhere, either in the present or the immediate past. The problem with falling for men involved with other people, as Diana tends to do, is that there is one facet of the other person you never see. Thus a man may show his fussy, pernickety side at home, his coolness and his bullying, but he can, with a mistress, repress all that (since it is expressed elsewhere) and just show the side that he wants to be seen.
Many is the wife who has felt furious that an unromantic, undemonstrative husband, who even forgets their wedding anniversary, may be found wining and dining his girlfriend and buying her bunches of flowers. The other women never see the dark side - and this is exactly what Diana never wants to see. If her men were to show their darker side, she would feel it was her fault, and get upset and despairing as a result, just as she did when her mother left her.
Charles clearly was not in love with Diana, and she fell for a fantasy figure rather than the real man. It was a Cinderella story, but the trouble was that she felt like Cinderella on the inside as well as the outside - a badly paid nursery school helper - and when the prince found her glass slipper fitted her after the ball, she imagined she would live happily ever after. Nothing is ever that easy.
The snakes that followed, the two Jameses, sound as if they were as emotionally damaged and damaging as Diana herself; and in them she found other untrusting, fearful mirrors of herself, who relied on pure surface charm to get them by. She must have felt comfortable with them because they were her emotional relatives. Carling might have seemed like a more normal bloke, but as ever there was a fly in the ointment - Julia, his wife, in the background. Similarly Oliver Hoare was another typical man that Diana fell for - utterly charming, good looking and suave - but with a wife in the background.
Who knows what Dodi's dark side is, but he must have one. We all do. But I guess all Diana experiences now is his overwhelming charm, a man who makes her feel good about herself without, almost certainly, ever getting to know the real person underneath.
By now most of us have got the picture and could easily pick a couple of men in our lives who are Diana's "type". They are "mad, bad and dangerous to know". Which is exactly how many men feel about Diana herself.
In other words, it is only by changing herself that Diana can change the men she picksn