Often, it is only once such a person leaves that one fully realises the impact they had on your general happiness, but in this case I was acutely aware day-to-day of how that happiness was being compromised, and it makes the peace on this side of the separation that much sweeter, that much ... happier.
Maybe a by-product of my years of working mostly from home, mostly with my children, but I count myself lucky that I've had relatively few opportunities to rue the presence of a particularly unpleasant person in my life (my own children don't count here).
I choose my friends well, I don't suffer fools, I don't compromise myself out of any sense of social obligation - those years of my life are over.
But all this makes me particularly annoyed when I do encounter an asshole, and find myself powerless to avoid them.
I'm not proud of myself that in this case the asshole was a child. But I'm also not afraid to say, with genuine sadness at the concept, that children can be assholes too.
Because of course it's never really their fault. Nature and nurture both play a roll and if you're conceived and raised by an asshole ... well then.
It wasn't made any easier by the fact that this kid was alarmingly smart, with a sense of humour which had me laughing despite myself, and a world view far beyond her years. Undoubtedly part of the problem.
And she was sweet, or she had real potential to be, but she was also mean, and cruel, and cuttingly shrewd.
I, we, just don't need that in our days. For a while, when I could envisage no way out of the situation which wouldn't cause major hurt and offence (discrediting, I'm not proud to admit, the amount of hurt and offence we were suffering from the association), I placated myself that is was better for my girls to learn how to manage an asshole in a controlled environment with their mother
But actually no, there's time enough to encounter assholes. There's plenty of time before that to learn lessons in self-confidence, civility, self-worth and how to build boundaries before they need to put them into practice.
The kid is gone, it happened quite naturally and easily in the end, and our days are much pleasanter as a result.