Nick Offerman is ready to spend time with his family.

The actor, 55, tells PEOPLE about his holiday rule with his wife, actress Megan Mullallywhile promoting his Netflix series,Death by Lightning.

“We kind of play it fast and loose,” he says. “This year we’re gonna go see my family in Illinois and then see Megan (Mullally’s) people in Oklahoma.”

But the couple has one holiday nonnegotiable, with Offerman saying, “I guess the only rule is no work. Hollywood knows to leave us alone until the new year arrives.”

The actor and Mullally, 67, began dating in 2000when they co-starred in the playThe Berlin Circle. The couple got engaged in London in 2002 and had a surprise wedding at their Los Angeles home in September 2003.

During a July appearance on

Offerman revealed that he popped the big question to Mullally quite a few times before they actually got engaged.

“Megan and I were one day walking to an art opening, and I was pulling something out of my pocket, and I dropped a quarter accidentally and I just went to grab it,” the actor recalled. “And Megan, as a joke, went, ‘Honey!’ ”

“We had been together about a year, and so we cracked each other up,” he continued. “So I played along and pretended that I had just lost the ring I was going to propose to her with. So that established this bit between us.”

When it came to his real proposal, Offerman said Mullally never questioned if it was real because he was “clearly terrified.”

“I was chewing on my mustache,” he joked.

Offerman’s latest project,Death by Lightningis about James Garfield’s presidency and assassination. The show features Michael Shannon as Garfield and Offerman as his vice president, Chester Arthur.

TheParks and Recreationalum told PEOPLE that he gained 20 pounds and wore an “incredible fat suit” for his role in the historical drama.

“It’s not a crazy amount, so it just sort of tapped into hedonism,” he said of his weight gain.

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“Right now, I’m a little trimmer and so I have a sense of my posture. When you let yourself go like Chester Arthur, it creates a slovenly demeanor, where you kind of let yourself drape over a chair with a little abandon,” Offerman continues.

Death by Lightningis now streaming on Netflix.