devastating, wonderful, terrifying, meaningful film (spoilers?)
Some of this repeats language from responses to other posters. Sorry for any repetition.
-- SPOILERS --
Some of the people on these boards are really, really missing the point of the film, I think. Far as I'm concerned, this film treats the whole question of marital fidelity-for-life and the roads not taken very seriously and unblinkingly.
It's sort of a horror film for married people, IMHO. You think about the chances for ending up like Lou, having given yourself over totally, having forsaken all others, and then...just too horrible to contemplate. It's real pain, unthinkably so, if you took it seriously to begin with. If anything, this film stands as a sober warning to people who are dipping their toes in deeper and deeper, and wondering what it would be like -- but not a didactic sort of warning. It's not pontificating. It's just a straight look at it in a way that really makes you take a very deep breath and think very hard. Not such a bad thing, in an era of throwaway films and postmodernist anti-meaning.
If people are reading this as some kind of "she cheated, and it was just fine" kind of film, boy, are they ever missing the point. I agree completely that Margot suffers for what she does. So does Lou. So does the "other man." So do the friends. So does her sort-of-ex niece. And on and on. In fact, the film is an examination of how easy it is to slide into cheating, just drifting into it, without any evil intent, almost wondering why you're doing what you're doing, wondering why you agreed to meet that person one more time. So you just dip one toe at a time, just getting a little intrigued and then finding yourself blowing up the place, and yourself with it, splattering everybody with various degrees of pain and loss.
IMHO, it was excruciating to watch, and incredibly valuable, also. It even leads to questions about marriage itself, what it is, what you mean when you take the vows. Like, do you really mean it when you say "forsaking all others"? Forever? Until you die? Most people, I think, don't even think about that very deeply. If you're going to do it and do it seriously, you forego all kinds of other paths, roads not taken. In a way, it's an acknowledgement of your own limitedness and your own mortality. It's a vision of the day of your own death, in a way, because this is the person you're saying you want there, and no other person (in that way). And then you have to stick to it. One and only one, until you pass from this world into whatever comes next, or into nothing. Makes you take a big breath even to think about it. That, to me, is exactly what the film is trying to do.
It's massively painful, and it's true. Real tragedy, like it happens in real life. A little niece who wonders why you're not around as much anymore, and who can't possibly understand the answer. It's the person you promised yourself to, like a stranger now. I had a lump in my throat through much of the film. It was just excruciating, if you take marriage seriously, and if you've ever pondered your own mortality vis-a-vis the idea of marriage, or even the reality of marriage. The most worthwhile, thoughtful, meaningful, devastating film I've seen in a long time.