I STRONGLY disagree.
I had two best friends all through primary and high school, let's call them Hannah and Kate.
Hannah's parents split up when she was 2. She doesn't remember it. Her dad moved out into a small house 2 miles away. Her parents split because things just werent working out, they hadn't planned a child and they probably weren't 'meant' for each other; Hannah doesn't remember the break up. Because they split while they still got on, it was all very amicable, and now 20-odd years later her parents are friends, chat regularly and get on well. Hannah did well in school and college, and knew if she had inevitable teenage angsty arguments with either parent she could go to the other's house for a night or two to let things defuse. She's now a nurse and is getting married this year and both parents will be there and probably sit on the same table, her mum with husband of ten years and dad with his new girlfriend.
Kate's parents never got on for as long as I can remember. I used to go round to her house when we were 5 and her parents would sit watching telly in separate rooms, one upstairs, one downstairs. They would take her out separately e.g. Saturday mum takes her to the zoo, Sunday dad takes her swimming. It was always obvious they didn't love each other but as they stayed together 'for the kids' you could see the resentment growing. When Kate was 13 she heard them talking about divorce and she told me in school 'my parents are FINALLY splitting up' - she hated seeing them both miserable - but they never did. Instead, her dad started working nights and her mum long days so they NEVER had to see each other. They built an extension off the back of the house that was like a man cave for the dad where he slept, and had his own TV, small cooking facilities and he used the downstairs toilet. It was such a weird set up. They finally split when Kate finished uni last year at 21 and had the 'you're old enough to understand now' talk. Kate told them how most of her years growing up were miserable because her parents either bickered or weren't there as they were trying to avoid one another. She wishes they'd split up when she was in primary school.
As for me, I always thought my family was 'the perfect family'. Dad has an amazing job, mum a SAHM with small business on the side, me and my sister good grades in school, 2 fancy holidays a year, brand new BMW on the driveway, big house. On the outside people always said 'you're so lucky'. But for me growing up was a nightmare. I was miserable and hated my mum, she was horrible to me for years. My dad left this year (after 30 years together) and said he'd fallen out of love with her a long time ago but stayed for me and my sister. I wish he'd left years ago because then my childhood wouldn't have been so miserable and I could have spent the bulk of my time with him. Now my mum is nearing 50 with no pension and no financial security for the future, bar a small amount of savings and a fancy house. My dad is currently on holiday with his new girlfriend and her kids.
My summary: divorce/break ups are never nice but the longer you stay for the wrong reasons the worse and messier it is later, for everyone.