Great Movies w/ Toxic Couples?

Black Narcissus is

I haven't seen it, but when I looked it up I saw that Badlands is set in South Dakota, and the characters have different names than the real murderers. Starkweather and Fugate inspired several movies, but those filmmakers have more room for artistic license. The real Charles Starkweather ... well, picture what Beavis might look like if he and Butt-Head hit the gym and each put on twenty-five pounds or so of muscle, just enough so they weren's skinny anymore. That dude was creepy looking. Fugate wasn't so bad, but at most ordinary looking, a fourteen year old that only a nineteen year old loser who couldn't get any other action -- i.e., someone like Charles Starkweather -- could fall for.

Anyway, the movie Starkweather is a dramatization of real events, depicting Starkweather and Fugate in Nebraska and Wyoming, and from what I understand the filmmakes stuck pretty close to the way things happened. Neither Starkweather nor Fugate were portrayed as attractive, either in looks or personality. He was portrayed as having some very sick fetishes in addition to his homicidal nature. She came off as someone so stupid that if you had offered her a photo of Abraham Lincoln's funeral autographed by Abe himself, she would have bought it and congratulated herself on snagging a rare and valuable historical relic