Some people are still missing the point here.
Obviously growing up in a happy 2 parent home is going to be an advantage. But that's not always an option.
Poverty is a confounding variable when considering outcomes of children from single parent families. it's very difficult to unpick whether adverse outcomes are caused by lack of a parent or poverty/low income, as single parent families are likely to be less well off.
I said that staying together for the sake of the children is nonsense, because that involves the parents being able to maintain a fantasy image to the children that all is well, perhaps for years, while they are actually stressed and miserable, without the children being aware that anything is wrong. This is so unlikely to be the case! The much more likely scenario is the choice between a happy and stable single parent home (or at least happier) or a miserable, conflict ridden existence but yay, you still have 2 parents present. I don't know why it's so difficult for some people to grasp that this choice just doesn't exist for most couples whose relationships are breaking down. It's insulting and patronising to suggest that they could have been a happy 2 parent family if only the selfish parents put their kids first. That's a fantasy and it helps no one.
This is not saying that 2 parents aren't better in most circumstances, rather that we shouldn't pressure parents unduly to stay together because that in itself is likely to be harmful, and other factors are likely to be influencing the outcomes for children.
Parental bereavement is obviously going to be traumatic - my sympathy to anyone, child or adult, who has experienced this. I don't think anyone is suggesting that this isn't an awful scenario.