Not for the first time, L realised that we don't feel the same about each other, and such was the fresh shock that she went away to be sick in the bathroom.
As is the only way possible, she deduced this from my own words and actions, and concluded that I didn't match the picture which she holds in her mind (or, worse still, that she doesn't match the picture in mine.) In any case, she was temporarily overwhelmed.
I am now aware, then, that L and I each stand in one pan of a set of weighing scales, and the requirement is that we must balance all the time. To tip slightly one way or the other is to induce sea-sickness.
What mindset is it that demands that the scales never move, even slightly? I ask not in order to criticise L, because my own thoughts are similar ones, but to reason about why I, she, innumerable people, presumably, look for this constancy with their partner.
I am confident enough here to make the generalisation that in all countries whose first language is English (perhaps all nations we describe as western), it is considered the ultimate purpose of human life to give and receive love. The alternative way of expressing this is that a human life lacks is devalued if and when it is not engaged in loving and being loved.
From an early age we imagine, and search for, that duality, and all our aims are sublimated in that direction. I contend that it is an outstanding individual indeed who can direct their attention elsewhere.
Part of what is imagined is a perfect equilibrium. It is blue bleeding into red and producing a third colour which is precisely 50 per cent red and 50 per cent blue. It is being exactly as important in the other person's estimation as they are in your own, no more and no less. Whatever is given is taken back to the demand of the nth decimal place.
'We don't feel the same' means, then, that we are a decimal place out - on this occasion, red repudiates blue, or the other way around. It isn't a case of an overwhelming amount of love poisoning the water and killing both fish with its toxins; but a few milligrams extra of red tipping the balance slightly - and so sensitive are we to the taste, and how it differs from the expected taste, that it causes us to vomit.