The trouble with this story is that it is written in terms of analysis of the laws of dissolution of the relationship between Paul and Ella. I don't see any other way to write it. As soon as one has lived through something, it falls into a pattern. And the pattern of an affair, even one that has lasted five years and has been as close as a marriage, is seen in terms of what ends it. That is why all this is untrue. Because while living through something one doesn't think like that at all.
Supposing I were to write it like this: two full days, in every detail, one at the beginning of the affair, and one towards the end? No, because I would still be instinctively isolating and emphasising the factors that destroyed the affair. It is that which would give the thing its shape. Otherwise it would be chaos, because these two days, separated by many months in time, would have no shadow over them, but would be records of a simple unthinking happiness with perhaps a couple of jarring moments (which in fact would be reflections of the approaching end but would not be felt like that at the time) but moments swallowed in the happiness.
Literature is analysis after the event.