I have felt what Edward felt.
You've been cuckolded because you were useless in the sack like Edward? That's so sad, man - but do you really expect Susan to spend the rest of her life with some dude who can't get her off? That sweet bod being wasted on a 'weak' loser - it just ain't right.

I don't get what you mean by calling this a non-ending. To me it's a perfect ending. I have felt what Edward felt. Susan is the cold hearted bitch that never believed in her man (it's not a complicated job) and then fulfilled her own beliefs by withdrawing her support and betraying a man who clearly felt deeply about, and therefore was almost destroyed by, her betrayal. When will women learn that the value that get out of a relationship is often directly correlated with the integrity they have in that relationship. In other words - have some faith in your man and don't be a beep useless, slutty bitch!

Perfert. And, I believe, that Edward was watching from afar while Susan waited at the table. Just to complete his ending. Susan became her mom.

Does Edward agree to the meeting ( dinner ) ? . As she waits and he doesn't show , it's open for interruptation but I think he stands her up .

I think that the ending is exactly like that: no more words to say the end is finally the end.
It's sad, it's terrifying said. Excruciatingly! And only will get it those ones that lived the same situation at least once in life.
Believe me.

He never showed up as it wasn't his agenda in the first place.
Then why did he agree to meet with her? You think he's a dishonest or cowardly person?
IMO, he send her novel, dedicated to her, . . .
Novelists dedicate their novels to people whom they regard highly - not somebody whom they despise.

IMO, he send her novel, dedicated to her, as she were the one, who didn't believe in him. Called him mediocre, told him not to write about himself. Left him for "the real man" in "the real world" and aborted his child.
Well novel was, about his life, she is haunted by the words in it, enchanted in so many ways that she ask him for meeting.
Maybe only thing that she didn't realized that plot was one huge allegory for their former life. She was in many ways Ray, as she killed every opportunity for Edward to have family with her, loving wife and child (daughter). She was Ray in a way that old Susan was dead, and new, non-creative, ready "for real world" Susan was born when she decided to leave.
Edward was both, Tony and Bobby. Tony-broken figure unable to do ANYTHING to save his child, and save his wife (in a way that he didn't prevent abortion and Susan's leaving), and Bobby, even though terminally ill, still hungry for justice, revenge and will to make things right once for all - he took all his strength, wrote hauntingly powerful novel ABOUT HIS LIFE, in which in a many ways he killed his old self - full of regret, but before that he said goodbye to Susan once for all knowing that justice was served.
Susan, as she was waiting at the table in the restaurant finally understood that. He never showed up as it wasn't his agenda in the first place. He just wanted her to understand what she did to his life, what she did to her own life and that she live to regret it. She lived to regret it.
I'm gonna live forever or die in attempt.

Simply Edward due his blindness did not find the restaurant
"To photograph: it is to put on the same line of sight the head, the eye and the heart."HCB

Based on Ford's comments, and the minimal description of current Tony in the film, it seems we are to care mostly about Susan. She's apparently moving on in many different ways now. Great.
It doesn't really matter if Tony is sick, or dying, or if he got a bad Uber driver, is out for revenge, or just chickened out of dinner.
My guess is revenge, but that's just a guess, which like all of these guesses is pointless to the other major points of the story.
Plot points and continuity issues aren't really relevant here.

so it was a revenge motive with both players being sour and sorrow person, i mean carrying such bitterness and sorrow for 20 years ?? i personally get cancer if i felt like that from a relationship
Agreed. I think that's why at the end of the story, people are like, "That's it?" I think they get what happened (which you nicely summarized), but then they reevaluate whether or not they care. And given two sour and sorrowful people, one of whom hurt the other, and the other responding with a manuscript, I can't imagine too many people giving a beep
From what I understand, the novel the film was based on was really more about the power of narrative and how it invades our thoughts and experiences in real life. It was a very self-conscious and perhaps literary novel aboutnovels. All the revenge aspects and relationship aspects are just window-dressing. So I think trying to make such a literary book (about reading) into a "thriller" (rather than a prosaic story that contains a thriller) leaves the audience with a sense that some things just don't fit, or that it's trying too hard to make us care without giving us the appropriate signs for whom or what to care about.

it was simple, she did not value him and his work, he loved her and her opinion about him and his work was very important, she tossed him away like he was nothing because as her mother said you are just like me, she was a very cold person had not much feeling in her souls, her heart never raced, she never felt nor shoved emotions, reading the book she felt all that , he gave her what she did not have and confirmed by date he made the last move by not turning up so she can go back to her miserable life back, so it was a revenge motive with both players being sour and sorrow person, i mean carrying such bitterness and sorrow for 20 years ?? i personally get cancer if i felt like that from a relationship well i suppose they had to make up such story to keep audience interested after all in real life this could never happen.

That is an excellent explanation DHfilmfan. Good job.

What bollocks. Oscar-winning movies generally have happy and obvious closures.
http://letterboxd.com/cremildo/

I was waiting for her to exit the restaurant and be gunned down by a hit man Edward hired!
Bu that would not be the artsy "Academy Award" ending we got.
Loved it till then. Expected so much more from the end. The build up everything was great. The acting spot on and thens**t.
This trend is dreadful. The Non-Ending. It is everywhere. Indie films use it. Cheapo D grade horror films use it. Now more and more the A list star driven films use it. With the cheapies I often feel the makers simply ran out of money! They had to stop shooting and tag on the credits! IN something like this?? It is infuriating.

I could see how someone could miss that it's a revenge movie. After all, there was only that scene at the art gallery that was way too on the nose, you know, the one that explained exactly what the movie was about for anyone too dumb to get it, where the word REVENGE was literally in giant letters hanging on the wall.

The big painting in which is written "revenge" foreshadows the ending. It's a revenge.
http://letterboxd.com/cremildo/

And for Edward, who knows NOTHING of Susan's dissatisfaction
Well I would say there was very little in the film to make us, the audience, think otherwise, except for 2 things:

1. We see Edward personally deliver the novel to Susan's house, and
2. Susan admits calling Edward 2 years ago and Edward did not take the call.
   Is this enough for the audience to question just how much Edward knows about Susan's current life? except
   The elevator man in New York was Edward's younger brother!!
   Bravo! Bravo!
   and curtain.

If Edward died right after sending Susan an email asking where and when to meet, then Nocturnal Animals has the biggest non sequitor ending of all time.

Even FartyKat figured that out.

Ugh, whatever. Believe what you like if it enhances your experience of the film.

He just stands her up at the end, because as a film we needed closure, . .
There's also the small matter he's likely dead or dying by the film's end.

She's rolling around in bed, swooning at her ex's magnificent manuscripther shower scenes mirror Tony'sshe defends a protg (that her colleagues want to replace) out of a new-found sense of commitmentshe gets all pretty and hopeful and removes her ring to meet Edward.
And for Edward, who knows NOTHING of Susan's dissatisfaction, and with NO INTENTION of winning Susan back, the manuscript was all he had to say.
There's no grand and elaborate revenge, because Edward has no such intentions either. After all, HE DIDN'T KNOW that Susan was miserable and that she would see him as a way out. It's not like Edward was sitting next to us watching this film, people.
He just stands her up at the end, because as a film, it needed closure, some scene, for us to realize that the tables had been turnednot a non-response to an email.

He gave it to the person who hurt him and she fell in love with him all over again, as women can do.
What? I think this kind of logic only flies in movies, reading a book by your ex doesn't usually make you fall in love with them. Maybe in the improbable movie situation where you just so happen to be unhappy with your life at that particular moment in time, but as OP and others have said:
How would Edward even know she was unhappy?
She called him once? People like to keep up with each other, especially if it's been 20 years. Otherwise he was taking a HUGE shot in the dark, nobody other than Susan's friend had figured out what was going on with their expenses.
Also, did he write the book with the intention of making her fall back in love with him so he could stand her up? He knew that would work? Honestly, I don't really see much in that story that would have made me fall back in love with him, but that's just me.
Or did he write the book just for himself and sent it to her to be like, "Look, I wrote a book!" and didn't give a care what she thought? If so, why was it dedicated to her and basically about her? I genuinely don't understand Edward's motives.
He really had no reason to think that Susan wanting to see him had anything to with falling back in love with him. He wrote her and her daughter as characters who were raped and murdered, I would have honestly been more creeped out by Ed than amorous.
It also seems to follow more realistic logic that she just wanted to meet him to give him feedback on the book, as that's why it appears he sent it to her in the first place.
I'm definitely with OP in that there are a lot of unanswered questions and confusing directions taken in this movie, coupled with the non-ending it felt wholly underwhelming.
She was unhappy with Edward, so I don't really know what it was about the book that made her want to go back to him. Seriously, Susan, find a new guy or learn to be single and happy with yourself because you're obviously not going to be happy with the people you've chosen so far.

yes, she has a heart, like we all do, and when it's stepped on it hurts. It's something you can just forget about. It can eat at you, for a very long time, which is exactly what happened to Edward. His heart was stepped on and it hurt him for a very long time. How long? We don't really know that, but we know that something came from that hurt. His work, his novel, had meaning behind it. He gave it to the person who hurt him and she fell in love with him all over again, as women can do.
And then he stepped all over her heart.
and that is exactly why this film is so good.
It's not about sunshine and roses, it's about how love and life can hurt, so very much.