Anyone who watched The diplomat has probably once wondered why Hal and Kate Wyler remain married.

“They know each other well,” Rufus Sewell, who plays Hal Wyler opposite Keri Russell’s Kate, tells PEOPLE. “They know what they love about each other and what they hate about each other, and sometimes (what) they love are the things they hate about each other and they hate the things they love about each other. It may be a marriage that is over, but sometimes a marriage that looks like it is over is actually in the middle of a change.”

That's what 57-year-old Sewell says The diplomat Creator Debora Cahn wanted to show that “the seeds of divorce, hate, lust, and hatred for the way your partner breathes are an integral part of many long-term relationships.”

“I recently heard her say that the people whose relationships ended up failing weren't because someone screwed over someone else. “It was because they didn’t like the way the other person was inhaling,” Sewell says.

As for the Wylers – who Sewell says use “political arguments as foreplay” – the British actor thinks: “They're fantastic together and a pain in the ass together, and it's all part of the same thing.”

In real life, Sewell married actress Vivian Benitez in July. He says he's portraying someone in a not-so-loving marriage The diplomat has no influence on how he views long-term relationships.

“I just tried to see things through my eyes and be really honest about my own descriptions of the world, rather than the descriptions of the world that would be given to me by the media,” he says. “My life experience tells me when I read this script that it is just wonderfully accurate.”

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In season 2 of The diplomatHal relies on Kate to help him physically while he rehabilitates after being injured in the explosion at the end of season one.

“He's frustrated by the physical limitations and the fact that he can't be as active and nimble as I felt when I made the film,” says Sewell. “The fact that he has to ask them to help him with even the most mundane personal things – not that they have a problem with helping in that way, but he feels like it's almost a foreshadowing of what's to come.” could come to her in relation to her.” his age. And I think it scares him a little bit.”

Hal's physical limitations in Season 2 also represent a disruption in his relationship with Kate. “Even if it's a pattern that you both complain about when it comes to who does what, if that changes, it could be quite disturbing says Sewell.

Despite his own setbacks, Hal continues to campaign for Kate to become Vice President of the United States.

“They have worked together in the past when he was No. 1 and she supported him. “I think there have been times in the past where she may have been willing to make sacrifices that he didn't want to because he believed in her potential and didn't want anything in their potential relationship that could hinder their progress,” says Sewell. “And I think there's a difference in his belief in her and her idea of ​​herself that led to him feeling like he had to be a little bit sneaky when it comes to people and events and even her.” to maneuver. All these dark talents are used with a very good heart.”

Sewell admits he doesn't know where the Wylers' lives will lead, but he has started filming the third season The diplomat in New York City. “We don’t know how long this will take,” he says. “But you thought the end of season one was a shock? Just wait for the end of season two! I can’t wait to see the public’s reaction.”

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The diplomat Season 2 is now streaming on Netflix.