The highly anticipated third season of Netflix’s House of Cards opened with a baptism of sorts, with newly minted President Frank Underwood urinating all over the gravestone of his late father. But the season finale offers an entirely different kind of spiritual cleansing.Throughout his presidential half-term, Frank (Kevin Spacey) has been marginalizing his Lady Macbeth, Claire (Robin Wright). He was reluctant to go to bat for her ambassadorship, chastised her for having the balls to stand up to homophobic Russian President Victor Petrov, and shamelessly pimped her out on the campaign trail. But Claire has, apparently, had enough.

At the hotel on their latest campaign stop in Iowa, Claire takes a bath. The camera lingers on her face as she stares blankly into the distance. Then her eyes widen and she submerges.

Claire returns to the bedroom and confronts her husband. “I want you to fuck me, Francis,” she declares. He swivels around in his chair, shocked. He says he’s working, and she slaps him across the face. “Shut up…I want you to be rough with me. Take me.” She grabs Frank’s hand and puts it around her neck. He refuses. She slaps him again. Then Frank pins her to the bed with her back facing him. “Is this what you want?” he screams, fiddling with his belt. “You want it rough?” But Claire spins around, facing him. “I want you to look at me while you do it.” And Frank retreats. “That’s what I thought,” she says.

The Underwoods have always had a bizarre—and complicated—sexual relationship, from Frank’s gay past at the Citadel to Claire’s photog tryst, and throughout Season 3, Frank’s marriage has come under attack by everyone from a Claire-smooching Petrov to ghost writer Thomas Yates to Claire herself. (Frank is despicable, so it’s not exactly unwarranted.)

“The scariest thing for us, narratively, was to take the core of this show, its greatest strength—this unorthodox, unholy union between these two people—and see it break apart,” creator Beau Willimon told The Daily Beast. “It had to be violent, and not just physically, but psychologically. What we’re seeing is a rift. It’s had 28 years to grow stronger, and through the course of a very short amount of time in the White House, it’s come apart.”

That shocking hotel room sequence even scared Willimon, who warned the actors beforehand about what was going to transpire. “When I first talked to Kevin and Robin about that scene in the hotel room, I went and explained to them about what I was going to do ahead of time, and I said, ‘If you feel uncomfortable about any of this, please say the word,’” said Willimon. “But they were both absolutely game and completely fearless. They were eager to go to this new and scary place. It was scary for them, but their fearlessness ruled the day.”

The scene bookended with Frank and Claire’s disturbing sex scene in the second episode of the season in which Frank, panic-stricken by the coup within his party and his lack of financial backers for a re-election campaign, has collapsed in his study, and Claire gets on top of him and brings him back to life—or as Willimon told me, “We’re portraying it as her feeding him.”

“In terms of the hotel scene, there was a deliberate mirroring there,” said Willimon. “We saw during the second episode this season a scene where sex made the two of them stronger. And here, we have a situation at the end where Claire, for a whole host of complex reasons, needs that reciprocated—but it has the opposite effect. It weakens them both. We’ve only seen the Underwoods have a sexual encounter twice in this series—one at the beginning and one at the end of this season—and they couldn’t be farther from each other in terms of the result.”

The other powerful Frank and Claire scene in the House of Cards third season finale is their Oval Office showdown. After the hotel room weirdness, Claire leaves the campaign trail and returns to the White House, refusing to be by Frank’s side as he takes Iowa. When he returns, she’s sitting in his Oval Office chair. “Look at us, Francis. We used to make each other stronger—at least I thought so—but that was a lie. We were making you stronger, and now I feel weak, and small, and I can’t stand that feeling any longer,” she says.

“What is the goddamn alternative? Please, Claire, tell me?” he replies. “I don’t understand. All I’m hearing is, ‘It’s not enough.’ That the White House is not enough, that being first lady is not enough, not enough.”

“No,” Claire says. “It’s you that’s not enough.” Frank, backed into a corner, snaps and says, “Without me, you are nothing,” grabs her by the face, and screams, “You will be the first lady!” “Kevin and Robin consistently save my ass because we make big choices on this show,” said Willimon. “We’re not after pure cinéma verité naturalism and have very heightened moments. I mean, the guy turns to the camera and speaks to us, for god’s sake! We always want to push the limits on that and sometimes we go too far, but I would never want to make the mistake of not going far enough, and would rather always be right on that line. We went for it in that scene, and Kevin and Robin made it magical, terrifying, rich, and unsettling, and, in their own fucked-up way, beautiful. A scene like that would completely fall apart if you didn’t have actors like Kevin and Robin.”

That Oval Office scene was also, according to Willimon, inspired by a lesson House of Cards executive producer David Fincher taught him.

“Fincher said something to me early on, and it’s one of the greatest lessons I’ve ever gotten on writing,” said Willimon. “He said, ‘In the best scenes, everyone is right.’ What I hope you’re seeing in those scenes with Frank and Claire at the end is that they’re both right—both of their views are legitimate—but they’re so far apart from one another that it’s destroyed the marriage.”After the fight, Claire approaches Frank and says, “Francis. I’m not going to New Hampshire. I’m leaving you,” and walks out of the room. So why did Willimon and his team of writers decide to split up Frank and Claire?“If we looked at the top of Season 3, we had a power couple who had achieved their goals and who ostensibly couldn’t be closer, so what scares us the most? Them being apart—and not only being apart, but being split,” said Willimon. “We asked ourselves if it was possible over the course of the season to get them to split apart, and what it would look like, but when we kept asking ourselves those questions we realized we’d already laid the groundwork in the previous two seasons. We’ve seen how Claire’s subverted ambitions have caused conflict between the two. We’ve seen the extent to which when they work together it can be a useful thing, and when they don’t work together it can be very destructive. It wasn’t coming out of nowhere. And pretty soon in that conversation, we realized that this is actually inevitable. We don’t have a choice. The pressures of the presidency and the cost of admission to the White House was going to put a stress on this marriage in ways that were going to eventually break it apart.”