They could be in love, too. But besides just being great, if we can try to list the lesser known gems, since most of us have probably seen “Who’s Afraid of Virginia Woolf?” for example, but that movie is kinda beating a dead horse. The exploitation gets old after a while.
The best I can think of at the moment are:
-Buffalo '66
-A Woman Under The Influence
-Minnie and Moskowitz
-Fat City
-Last Tango In Paris
I also highly recommend the movie “Les Chat”. Starring Jean Gabin. It’s French for “the cat”, and its about an older couple who can’t stand each other. I don’t wanna spoil anything, but the movie to me is an 8.5/10
The last two movies I have seen would be good examples, and just good movies like “Head-On” (7.5/10) about a young suicidal woman who wants to get away from her strict parents so she asks a guy she sees at the mental hospital if he would marry her.
Three days ago, I saw “The Honeymoon Killers” (7/10). They meet from a newspaper ad, and the woman sees that her “man” embezzles money from old woman who are tempted by this younger Latin guy, with the help of his “sister” his overweight girlfriend who is very insecure, which also placates any suspicion the women might have.
I recently saw Vertigo for the first time and I couldn’t stomach that “relationship”. I hated how desperately in love Scottie was after just a few encounters. And it spiraled from there.
Two For The Road (Albert Finney, Audrey Hepburn) maybe qualifies, although (spoiler) in the end they seem to decide to try at least one more time. This movie is about the toxicity of these two characters towards each other, from how they met, to every time they broke up or nearly broke up, and all the nasty stuff they did and said to each other.
Head On (Gegen die Wand) is a brilliant movie, and stars Sibel Kekilli in one of her first (maybe her first) major roles.
She’s quite well known in Germany, apparently, but best known to American audiences as Shae, in Game of Thrones. Somewhere between Head on and Game of Thrones she had an ill-advised nose job, but nonetheless is gorgeous and a brilliant actress.
Fat City is another must-watch, with Stacy Keach, and a very young Jeff Bridges. Also Candy Clark.
Definitely about toxic couples, although the “couple” aspect is more up front and center in Head On than in Fat City (unless you’re counting the characters played by Stacy Keach and Jeff Bridges as a couple, which is actually totally plausible).
Others – Bonnie and Clyde, of course.
Dead Ringers, maybe? If you loosen up your definition of “couple.”