But how does marital breakdown affect adult children? On the one hand, there is the expectation to act "the grown up" and "cope", while at the same time watching what has built up through a lifetime suddenly disintegrate. One study has found that people whose parents divorce between the ages of 16 to 26 are five times more likely to develop psychiatric illness.
Gill Gorell Barnes, family therapist with the Tavistock Clinic, has counselled many adults who have experienced this. "The biggest difference is the sudden, crushing sense of insecurity," she says. "People can't believe that what they grew up with has been wiped away.
"On the more positive side, it can sometimes force you to stop seeing them both as a blob called "parents" and instead forge entirely new adult relationships with each of them. Some people see their parents blooming, and becoming interesting, feisty people in their own right - though, I must say, it's usually the mothers rather than the fathers."
Denise Knowles at Relate says that late parental divorce can affect people's abilities to form their own relationships. "It's a vulnerable time for someone who's just starting out, and it forces you to question absolutely everything. You feel that if this can happen to your parents after all that time, then nothing is certain. Anything can happen to you."
Brad was 23 when his father left their home in New Zealand for another woman. Now 31, he teaches in London.
Remembering the moment still makes me shiver. I was about to leave work when my phone rang. It was Mum, and she was hysterical, just screaming. "He's left me. He's left me. Your father's left me." I didn't know what she was talking about. I thought he'd gone for a walk or something. Then she said, "There's a note. It just says `Give my love to the kids'."
It took an hour to drive to the family home - the house I'd grown up in and that Dad had built - and I was shaking all the way. My life passed before my eyes. My parents never rowed. We'd had the typical suburban scene - a son, a daughter, a dog, a beach house where we spent summers. I'd never considered that my parents wouldn't always be together.
When I got home, it was like he'd died. His cupboards were full of clothes, his garage was full of tools, he'd left everything behind. Just walked out on 27 years of life.
We learnt from the airport that he'd flown to England on that same day, and for eight months we heard nothing. As an adult, I had to cope and support my mother, but as their child, I was traumatised. Overnight, I'd lost my family unit, and there was this huge feeling of failure. I'd thought we were happy - but how could we have been? I was also old enough to feel the stigma. Suddenly we were a statistic, a soap opera come true.
Eventually, Dad started to write, and explain. Shortly before it happened, he'd gone to England to visit his mother and met another woman. The day he left us, she was waiting at Heathrow with a bottle of champagne. He says he was going through a breakdown, and had even considered suicide. Maybe when my sister and I had left home, he'd had to think hard about his relationship with Mum. They had married young, and he made me realise that my parents are humans, with separate emotions and pains - not just a unit.
The strongest feeling has been the vulnerability. I don't want anyone to get close to me because if someone can do that after 27 years, they can do anything. I didn't have a proper relationship for six years, and I'm still cynical about love and togetherness.
It's also left me without a "home". Both parents have remarried, and I've never lived with either of their new partners. So there's nowhere in the world where I can go back to, and completely belong, which partly explains why I've been travelling for six years.
My whole history - everything that created me - vanished on that day. I know I'm big enough to look after myself, but, unbelievably, eight years on, the loss can still almost make me cry.
Holly, 32, was 18 and about to leave home when her mother told her that she wished to separate from her father.
My parents seemed to have a good, strong relationship. I only remember hearing them argue once. I was close to both of them, and assumed they'd always be together. Now I see that Mum had been growing apart, but because there were no blazing rows, we never noticed it. In a way, I'm glad I kept hold of the illusion for so long.
Mum had married Dad when she was 18, and it had been very traditional, with Dad working as an engineer, and Mum in secretarial jobs. When I was 12, she got a job in a housing co-operative with lots of educated, middle- class people, and it was like a gradual awakening. She realised there were things she'd missed out on - she became more stroppy about her lack of help around the house. At the same time, Dad was forced to take jobs abroad.
It happened when he was in Barbados and Mum was flying out to visit the next day. She was lying in the bath, and just said, "Tomorrow, I want to speak to Dad about separating."
I remember feeling a really deep, deep sadness but making a conscious decision not to cry - that I was old enough to deal with it in a mature way. Mum had brought me and my sister up to be independent, career-oriented women, so I could rationally understand her decision. But emotionally, I still saw Dad as the victim. When I went out to visit him, it was very distressing because he couldn't accept it at all. At that point, there was a real role-reversal, as I worried about him and tried very gently to explain.
I never reproached Mum, but I suppose the resentment came out in other ways. In the months before I went to university, the two of us had to leave the house and move into a small flat, and we fought all the time. This was her bid for independence, and she still had a daughter round her neck. For me, there was a childish feeling that she was supposed to be my Mum, not some groovy feminist.
It's taken time, but Dad's been amazing. There's been no acrimony. Mum opened a restaurant, Dad came back to England, got a job, a flat, and 13 years on, they've settled into this really sweet friendship. I've learnt to see my parents as two individuals, and I'm proud of them. Neither has remarried, so me and my sister are still at the centre of their lives.
It's left me with a very realistic - or cynical - outlook on lifelong partnership, though. It's a tall order to expect to stay with someone for ever. I've seen how much people can change over the years, and if the relationship can't accommodate those changes, it doesn't stand a chance.
Louise, 27, was at university when her parents split up after 33 years of marriage.
When I was 16, someone described us as the Kellogg's Cornflake family because we were sickeningly stable and happy. We'd always lived in the same house in the country. Dad phoned Mum from work every day, and arrived home at seven each evening. It was all you'd expect in an advert - and it hadn't changed in 20 years.
As the youngest, I was the last to leave. It was my second year at university when Mum phoned in tears to say that Dad had "met someone else".
It was impossible to take in - if she'd said he'd dropped dead, it would have at least been believable.
I felt basic, abject terror as my secure world disintegrated. For the next few days, as I lay in bed and cried, I also remember wondering what my university friends thought. Some had been through all this years before and "got over it". Was I childish, still needing my parents together when I'd left home anyway?
It seemed like a classic mid-life crisis. The kids had left, things were winding down, then Dad met someone he could start again with. My brothers and I all went home and rallied round. It was like a mourning for our shared history, really.
Not surprisingly, Dad found it harder to leave than he expected, and for the next six years he came back and forth, turning up in tears, with Mum taking him back. Finally, they wore each other out and she told him to leave for good. They haven't spoken for over a year.
The unbelievable thing is that I have still never talked about this to Dad. During the times when we were both back home, we acted out the old routines as if nothing had happened. Now we both live in London, we meet regularly and talk about absolutely anything except the fact that he has left Mum. I don't even know if he's living with this other woman - I never go to his flat and only contact him at work.
I still love him, but after 20 years of living within clear, safe roles, it's become too late and difficult to change them. There's also a lot of hurt that's probably best left repressed. I have an occasional dream where I finally confront this "other woman" - whoever she is - and scratch her face off. It always wakes me crying.
Mum, on the other hand, has made a complete recovery. She's transformed from the traditional wife to someone who's utterly in charge. She has stayed in the family home, only now she runs it. She practically runs the village, actually, and has a far better social life than me. We're much closer than we'd have been otherwise, and we've done things like backpacked round India together.
Watching her bloom has been the most inspiring experience of my life. I truly believe that if she can cope with that, I should cope with just about anything.Reuse content