In On Human Nature: Essays Partly Posthumous in Ethics and Politics (1896:1957, Allen and Unwin, London, pp. 14), Schopenhauer writes
Every human perfection is allied to a defect into which it threatens to pass; but it is also true that every defect is allied to a perfection. Hence it is that if, as often happens, we make a mistake about a man, it is because at the beginning of our acquaintance with him we confound his defects with the kinds of perfection to which they are allied. The cautious man seems to us a coward; the economical man, a miser; the spendthrift seems liberal; the rude fellow, downright and sincere; the foolhardy person looks as if he were going to work with a noble self-confidence; and so on in many other cases.
And then there is the converse of this uneasy co-existence of the sublime and the sordid that Schopenhauer refers to. One that is painfully familiar to disillusioned lovers, to that pair of humans whose crossed stars are just their psychological dispositions.
For as those whose relationships flounder know all too well, the very qualities that first attracted us to those who subsequently repel us are the ones that have now morphed into their ‘allied defects.’ The gay, carefree, quick to laugh social raconteur now strikes us as impossibly frivolous, incapable of entertaining a solitary serious thought; the blunt and refreshingly straightforward shooter from the hip comes across as a tactless boor; the affectionate dispenser of physical touches makes us cringe from their cloying, overpowering invasion of our private spaces. There is a reason why the mutual hatred and fury and anger of a pair of humans engaged in the deconstruction of their former love is quite as appalling as it is, both on the inside and the outside: the disappointment and shock at the transformation of the previously beautiful into the ugly is among the most acute sensations we will ever experience. We are betrayed; we have been cheated; our most precious illusion has been shattered; the ramparts of this most sturdy fort we had built against the advances of this world have been breached by the most insidious Trojan horse of all.
It was there all along, that snake that raised its head and bit you as you trod on it; it’s tempting to think that you just ‘mistook’ it for something else. But it was what it was, the ‘same thing,’ now understood and experienced differently. For the partners in the relationship are now different; their lives and circumstances and dispositions changed (often in response to the presence of ‘the other one’, the ‘significant other.’) Many are the rueful words written by former lovers that speak of how they ‘knew it all along’, how they were ‘blind’ to ‘not see this coming’ when ‘it was there all along.’ And, of course, of how they went on and on, blithely ignoring the warning klaxons, hoping the rocks rising out the waters, looming above them, would simply sink beneath the waves.