Lookout, I'm not arguing for argument's sake but do we know categorically that it was "at the drop of a hat" or was it that, after years of putting up with erratic behaviour, he'd reached the end of his, OK, perhaps NOT very long, tether.
I do personally think that the marriage was rather short-lived and I haben't read anything to the effect that they were trying to solve their differences for the sake of the twins,if nothing else.
He must have known prior to marrying Sheila that she could be a handful,as her depression was already lying dormant.
I noticed that he hadn't got a good word to say about June,but she wasn't the one he married,so I'd have said he should have sorted things out better than he did. " For better,for Worse " ?