I concur with Dimity, although on reading the book for the 2nd time (it's a habit in our house) I did reflect back tot hose times in the early sixties and I remember quiote clearly young people (men in particular) laughing as they described marriage as a 'licence to have sex'. Remaining virgins until marriage was seen as a moral imperative, not usually followed, but probably more common than today. Of course we all know what changed that position irrevocably, that being the pill and the onset of the sexual revolution which, of course, Eddie finally got involved in. Flo, on the other hand, alluded to another trend of the 60's, that being 'open marriages', and a side reference to psychoanalysis (Yes! The product of a cold, calculating mother and a domineering father!). So altogether she was a harbinger of the 60's revolution, ironically from someone who was 'frigid'. Could such a story have credence today? Possibly not as sex is probably integral to any relationship which ends in marriage, whereas 50 years ago sex was seen as starting at marriage (in theory at least). A bit of juxtaposing horses and carts if you will.
The most disappointing aspect of this book from a self-confessed McEwan fan is that I did not engage with either character, and so I was not emotionally or intellectually wedded to any outcome. They did not draw a sympathetic response from me and I felt a bit of 'as you sow, so you reap'. Victims of their generation? Victims of each other? Victims of themselves? Probably.
Eddie ends up with one short marriage and a string of over-lapping relationships. It may well have been that Flo was his one true love and that if his ego had relinquished a little on Chesil Beach then they could have made a reconciliation and sought solutions to their dilemma. Is the key to all relationships perseverence, and the death to relationships stubborn ego and petulant flight?
One last point. The rleationship between the two was hard to be viewed as a classical love affair. It was duty-centric. And largely duty to each other's family. There was little (actually no) passion, which may give substance to that old joke - what is the shortest book in the world? The book of great British lovers.