I think the answer to this question depends on how badly a marriage is broken and how old the children are. If the children are very young, it probably does make sense to separate or divorce. I don’t think young children should have to suffer because their parents can’t get along.
That way the children might still have an opportunity to live a normal life if their divorced parents can find love again and remarry. If the children are older and if parents can be civil to each other in front of the children, then I think it would be okay to stay together for the children’s sake. By the time kids are teenagers, they are old enough to withstand the trauma of divorce.