While in theory I understand the point that divorce may not be the right answer to one single, isolated incident, in practice it's very very rarely a single incident that makes people speak out and draw that line.
Women tend not to speak even on an anonymous board about the early incidents, and yes, I'm sure there are always early signs when tend to get ignored. By the time someone is posting, there will always be more than one incident and so it's more the straw that broke the camels back scenario.
In this instance, OP mentioned an earlier incident which had not been in front of the children followed by this incident in front of children. This is not calm discussion or counselling territory.
If he can choose to behave well, he was also making a choice when he choose to behave so badly. Lots of women put up with a lot and only spring into action when the children are more directly involved.
Most parts of society encourage women to forgive and 'make the marriage work'. Thank goodness for the still, small voice of Mumsnet providing support for women who say 'no more'
Supporting the realisation that this is abuse, and that it is a choice, is an important service to counterbalance the 'try harder to make the marriage work'